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curl(1) curl Manual curl(1)
NAME
curl - transfer a URL
SYNOPSIS
curl [options / URLs]
DESCRIPTION
curl is a tool for transferring data from or to a server using URLs. It
supports these protocols: DICT, FILE, FTP, FTPS, GOPHER, GOPHERS, HTTP,
HTTPS, IMAP, IMAPS, LDAP, LDAPS, MQTT, POP3, POP3S, RTMP, RTMPS, RTSP,
SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET, TFTP, WS and WSS.
curl is powered by libcurl for all transfer-related features. See
libcurl(3) for details.
URL
The URL syntax is protocol-dependent. You find a detailed description
in RFC 3986.
If you provide a URL without a leading protocol:// scheme, curl guesses
what protocol you want. It then defaults to HTTP but assumes others
based on often-used hostname prefixes. For example, for hostnames
starting with "ftp." curl assumes you want FTP.
You can specify any amount of URLs on the command line. They are
fetched in a sequential manner in the specified order unless you use
-Z, --parallel. You can specify command line options and URLs mixed and
in any order on the command line.
curl attempts to reuse connections when doing multiple transfers, so
that getting many files from the same server do not use multiple con-
nects and setup handshakes. This improves speed. Connection reuse can
only be done for URLs specified for a single command line invocation
and cannot be performed between separate curl runs.
Provide an IPv6 zone id in the URL with an escaped percentage sign.
Like in
"http://[fe80::3%25eth0]/"
Everything provided on the command line that is not a command line op-
tion or its argument, curl assumes is a URL and treats it as such.
GLOBBING
You can specify multiple URLs or parts of URLs by writing lists within
braces or ranges within brackets. We call this "globbing".
Provide a list with three different names like this:
"http://site.{one,two,three}.com"
Do sequences of alphanumeric series by using [] as in:
"ftp://ftp.example.com/file[1-100].txt"
With leading zeroes:
"ftp://ftp.example.com/file[001-100].txt"
With letters through the alphabet:
"ftp://ftp.example.com/file[a-z].txt"
Nested sequences are not supported, but you can use several ones next
to each other:
"http://example.com/archive[1996-1999]/vol[1-4]/part{a,b,c}.html"
You can specify a step counter for the ranges to get every Nth number
or letter:
"http://example.com/file[1-100:10].txt"
"http://example.com/file[a-z:2].txt"
When using [] or {} sequences when invoked from a command line prompt,
you probably have to put the full URL within double quotes to avoid the
shell from interfering with it. This also goes for other characters
treated special, like for example '&', '?' and '*'.
Switch off globbing with -g, --globoff.
VARIABLES
curl supports command line variables (added in 8.3.0). Set variables
with --variable name=content or --variable name@file (where "file" can
be stdin if set to a single dash (-)).
Variable contents can be expanded in option parameters using "{{name}}"
if the option name is prefixed with "--expand-". This gets the contents
of the variable "name" inserted, or a blank if the name does not exist
as a variable. Insert "{{" verbatim in the string by prefixing it with
a backslash, like "\{{".
You access and expand environment variables by first importing them.
You select to either require the environment variable to be set or you
can provide a default value in case it is not already set. Plain
"--variable %name" imports the variable called "name" but exits with an
error if that environment variable is not already set. To provide a de-
fault value if it is not set, use "--variable %name=content" or
"--variable %name@content".
Example. Get the USER environment variable into the URL, fail if USER
is not set:
--variable '%USER'
--expand-url = "https://example.com/api/{{USER}}/method"
When expanding variables, curl supports a set of functions that can
make the variable contents more convenient to use. It can trim leading
and trailing white space with "trim", it can output the contents as a
JSON quoted string with "json", URL encode the string with "url",
base64 encode it with "b64" and base64 decode it with "64dec". To apply
functions to a variable expansion, add them colon separated to the
right side of the variable. Variable content holding null bytes that
are not encoded when expanded causes an error.
Example: get the contents of a file called $HOME/.secret into a vari-
able called "fix". Make sure that the content is trimmed and per-
cent-encoded when sent as POST data:
--variable %HOME
--expand-variable fix@{{HOME}}/.secret
--expand-data "{{fix:trim:url}}"
https://example.com/
Command line variables and expansions were added in 8.3.0.
OUTPUT
If not told otherwise, curl writes the received data to stdout. It can
be instructed to instead save that data into a local file, using the
-o, --output or -O, --remote-name options. If curl is given multiple
URLs to transfer on the command line, it similarly needs multiple op-
tions for where to save them.
curl does not parse or otherwise "understand" the content it gets or
writes as output. It does no encoding or decoding, unless explicitly
asked to with dedicated command line options.
PROTOCOLS
curl supports numerous protocols, or put in URL terms: schemes. Your
particular build may not support them all.
DICT Lets you lookup words using online dictionaries.
FILE Read or write local files. curl does not support accessing
file:// URL remotely, but when running on Microsoft Windows us-
ing the native UNC approach works.
FTP(S) curl supports the File Transfer Protocol with a lot of tweaks
and levers. With or without using TLS.
GOPHER(S)
Retrieve files.
HTTP(S)
curl supports HTTP with numerous options and variations. It can
speak HTTP version 0.9, 1.0, 1.1, 2 and 3 depending on build op-
tions and the correct command line options.
IMAP(S)
Using the mail reading protocol, curl can download emails for
you. With or without using TLS.
LDAP(S)
curl can do directory lookups for you, with or without TLS.
MQTT curl supports MQTT version 3. Downloading over MQTT equals sub-
scribing to a topic while uploading/posting equals publishing on
a topic. MQTT over TLS is not supported (yet).
POP3(S)
Downloading from a pop3 server means getting an email. With or
without using TLS.
RTMP(S)
The Realtime Messaging Protocol is primarily used to serve
streaming media and curl can download it.
RTSP curl supports RTSP 1.0 downloads.
SCP curl supports SSH version 2 scp transfers.
SFTP curl supports SFTP (draft 5) done over SSH version 2.
SMB(S) curl supports SMB version 1 for upload and download.
SMTP(S)
Uploading contents to an SMTP server means sending an email.
With or without TLS.
TELNET Fetching a telnet URL starts an interactive session where it
sends what it reads on stdin and outputs what the server sends
it.
TFTP curl can do TFTP downloads and uploads.
WS(S) WebSocket done over HTTP/1. WSS implies that it works over
HTTPS.
PROGRESS METER
curl normally displays a progress meter during operations, indicating
the amount of transferred data, transfer speeds and estimated time
left, etc. The progress meter displays the transfer rate in bytes per
second. The suffixes (k, M, G, T, P) are 1024 based. For example 1k is
1024 bytes. 1M is 1048576 bytes.
curl displays this data to the terminal by default, so if you invoke
curl to do an operation and it is about to write data to the terminal,
it disables the progress meter as otherwise it would mess up the output
mixing progress meter and response data.
If you want a progress meter for HTTP POST or PUT requests, you need to
redirect the response output to a file, using shell redirect (>), -o,
--output or similar.
This does not apply to FTP upload as that operation does not spit out
any response data to the terminal.
If you prefer a progress bar instead of the regular meter, -#,
--progress-bar is your friend. You can also disable the progress meter
completely with the -s, --silent option.
VERSION
This man page describes curl 8.14.1. If you use a later version,
chances are this man page does not fully document it. If you use an
earlier version, this document tries to include version information
about which specific version that introduced changes.
You can always learn which the latest curl version is by running
curl https://curl.se/info
The online version of this man page is always showing the latest incar-
nation: https://curl.se/docs/manpage.html
OPTIONS
Options start with one or two dashes. Many of the options require an
additional value next to them. If provided text does not start with a
dash, it is presumed to be and treated as a URL.
The short "single-dash" form of the options, -d for example, may be
used with or without a space between it and its value, although a space
is a recommended separator. The long double-dash form, -d, --data for
example, requires a space between it and its value.
Short version options that do not need any additional values can be
used immediately next to each other, like for example you can specify
all the options -O, -L and -v at once as -OLv.
In general, all boolean options are enabled with --option and yet again
disabled with --no-option. That is, you use the same option name but
prefix it with "no-". However, in this list we mostly only list and
show the --option version of them.
When -:, --next is used, it resets the parser state and you start again
with a clean option state, except for the options that are global.
Global options retain their values and meaning even after -:, --next.
The first argument that is exactly two dashes ("--"), marks the end of
options; any argument after the end of options is interpreted as a URL
argument even if it starts with a dash.
The following options are global: --fail-early, --libcurl, --paral-
lel-immediate, --parallel-max, -Z, --parallel, -#, --progress-bar,
--rate, -S, --show-error, --stderr, --styled-output, --trace-ascii,
--trace-config, --trace-ids, --trace-time, --trace and -v, --verbose.
ALL OPTIONS
--abstract-unix-socket <path>
(HTTP) Connect through an abstract Unix domain socket, instead
of using the network. Note: netstat shows the path of an ab-
stract socket prefixed with "@", however the <path> argument
should not have this leading character.
If --abstract-unix-socket is provided several times, the last
set value is used.
Example:
curl --abstract-unix-socket socketpath https://example.com
See also --unix-socket.
--alt-svc <filename>
(HTTPS) Enable the alt-svc parser. If the filename points to an
existing alt-svc cache file, that gets used. After a completed
transfer, the cache is saved to the filename again if it has
been modified.
Specify a "" filename (zero length) to avoid loading/saving and
make curl just handle the cache in memory.
If this option is used several times, curl loads contents from
all the files but the last one is used for saving.
--alt-svc can be used several times in a command line
Example:
curl --alt-svc svc.txt https://example.com
Added in 7.64.1. See also --resolve and --connect-to.
--anyauth
(HTTP) Figure out authentication method automatically, and use
the most secure one the remote site claims to support. This is
done by first doing a request and checking the response-headers,
thus possibly inducing an extra network round-trip. This option
is used instead of setting a specific authentication method,
which you can do with --basic, --digest, --ntlm, and --negoti-
ate.
Using --anyauth is not recommended if you do uploads from stdin,
since it may require data to be sent twice and then the client
must be able to rewind. If the need should arise when uploading
from stdin, the upload operation fails.
Used together with -u, --user.
Providing --anyauth multiple times has no extra effect.
Example:
curl --anyauth --user me:pwd https://example.com
See also --proxy-anyauth, --basic and --digest.
-a, --append
(FTP SFTP) When used in an upload, this option makes curl append
to the target file instead of overwriting it. If the remote file
does not exist, it is created. Note that this flag is ignored by
some SFTP servers (including OpenSSH).
Providing --append multiple times has no extra effect. Disable
it again with --no-append.
Example:
curl --upload-file local --append ftp://example.com/
See also -r, --range and -C, --continue-at.
--aws-sigv4 <provider1[:prvdr2[:reg[:srv]]]>
(HTTP) Use AWS V4 signature authentication in the transfer.
The provider argument is a string that is used by the algorithm
when creating outgoing authentication headers.
The region argument is a string that points to a geographic area
of a resources collection (region-code) when the region name is
omitted from the endpoint.
The service argument is a string that points to a function pro-
vided by a cloud (service-code) when the service name is omitted
from the endpoint.
If --aws-sigv4 is provided several times, the last set value is
used.
Example:
curl --aws-sigv4 "aws:amz:us-east-2:es" --user "key:secret" https://example.com
Added in 7.75.0. See also --basic and -u, --user.
--basic
(HTTP) Use HTTP Basic authentication with the remote host. This
method is the default and this option is usually pointless, un-
less you use it to override a previously set option that sets a
different authentication method (such as --ntlm, --digest, or
--negotiate).
Used together with -u, --user.
Providing --basic multiple times has no extra effect.
Example:
curl -u name:password --basic https://example.com
See also --proxy-basic.
--ca-native
(TLS) Use the operating system's native CA store for certificate
verification.
This option is independent of other CA certificate locations set
at run time or build time. Those locations are searched in addi-
tion to the native CA store.
This option works with OpenSSL and its forks (LibreSSL, Bor-
ingSSL, etc) on Windows. (Added in 7.71.0)
This option works with wolfSSL on Windows, Linux (Debian,
Ubuntu, Gentoo, Fedora, RHEL), macOS, Android and iOS. (Added in
8.3.0)
This option works with GnuTLS. (Added in 8.5.0)
This option works with rustls on Windows, macOS, Android and
iOS. On Linux it is equivalent to using the Mozilla CA certifi-
cate bundle. When used with rustls _only_ the native CA store is
consulted, not other locations set at run time or build time.
(Added in 8.13.0)
This option currently has no effect for Schannel or Secure
Transport. Those are native TLS libraries from Microsoft and Ap-
ple, respectively, that by default use the native CA store for
verification unless overridden by a CA certificate location set-
ting.
Providing --ca-native multiple times has no extra effect. Dis-
able it again with --no-ca-native.
Example:
curl --ca-native https://example.com
Added in 8.2.0. See also --cacert, --capath, --dump-ca-embed,
-k, --insecure and --proxy-ca-native.
--cacert <file>
(TLS) Use the specified certificate file to verify the peer. The
file may contain multiple CA certificates. The certificate(s)
must be in PEM format. Normally curl is built to use a default
file for this, so this option is typically used to alter that
default file.
curl recognizes the environment variable named 'CURL_CA_BUNDLE'
if it is set and the TLS backend is not Schannel, and uses the
given path as a path to a CA cert bundle. This option overrides
that variable.
(Windows) curl automatically looks for a CA certs file named
'curl-ca-bundle.crt', either in the same directory as curl.exe,
or in the Current Working Directory, or in any folder along your
PATH.
curl 8.11.0 added a build-time option to disable this search be-
havior, and another option to restrict search to the applica-
tion's directory.
(iOS and macOS only) If curl is built against Secure Transport,
then this option is supported for backward compatibility with
other SSL engines, but it should not be set. If the option is
not set, then curl uses the certificates in the system and user
Keychain to verify the peer, which is the preferred method of
verifying the peer's certificate chain.
(Schannel only) This option is supported for Schannel in Windows
7 or later (added in 7.60.0). This option is supported for back-
ward compatibility with other SSL engines; instead it is recom-
mended to use Windows' store of root certificates (the default
for Schannel).
If --cacert is provided several times, the last set value is
used.
Example:
curl --cacert CA-file.txt https://example.com
See also --capath, --dump-ca-embed and -k, --insecure.
--capath <dir>
(TLS) Use the specified certificate directory to verify the
peer. Multiple paths can be provided by separating them with
colon (":") (e.g. "path1:path2:path3"). The certificates must be
in PEM format, and if curl is built against OpenSSL, the direc-
tory must have been processed using the c_rehash utility sup-
plied with OpenSSL. Using --capath can allow OpenSSL-powered
curl to make SSL-connections much more efficiently than using
--cacert if the --cacert file contains many CA certificates.
If this option is set, the default capath value is ignored.
If --capath is provided several times, the last set value is
used.
Example:
curl --capath /local/directory https://example.com
See also --cacert, --dump-ca-embed and -k, --insecure.
-E, --cert <certificate[:password]>
(TLS) Use the specified client certificate file when getting a
file with HTTPS, FTPS or another SSL-based protocol. The cer-
tificate must be in PKCS#12 format if using Secure Transport, or
PEM format if using any other engine. If the optional password
is not specified, it is queried for on the terminal. Note that
this option assumes a certificate file that is the private key
and the client certificate concatenated. See -E, --cert and
--key to specify them independently.
In the <certificate> portion of the argument, you must escape
the character ":" as "\:" so that it is not recognized as the
password delimiter. Similarly, you must escape the double quote
character as \" so that it is not recognized as an escape char-
acter.
If curl is built against OpenSSL, and the engine pkcs11 or
pkcs11 provider is available, then a PKCS#11 URI (RFC 7512) can
be used to specify a certificate located in a PKCS#11 device. A
string beginning with "pkcs11:" is interpreted as a PKCS#11 URI.
If a PKCS#11 URI is provided, then the --engine option is set as
"pkcs11" if none was provided and the --cert-type option is set
as "ENG" or "PROV" if none was provided (depending on OpenSSL
version).
If curl is built against GnuTLS, a PKCS#11 URI can be used to
specify a certificate located in a PKCS#11 device. A string be-
ginning with "pkcs11:" is interpreted as a PKCS#11 URI.
(iOS and macOS only) If curl is built against Secure Transport,
then the certificate string can either be the name of a certifi-
cate/private key in the system or user keychain, or the path to
a PKCS#12-encoded certificate and private key. If you want to
use a file from the current directory, please precede it with
"./" prefix, in order to avoid confusion with a nickname.
(Schannel only) Client certificates must be specified by a path
expression to a certificate store. (Loading PFX is not sup-
ported; you can import it to a store first). You can use "<store
location>\<store name>\<thumbprint>" to refer to a certificate
in the system certificates store, for example, "Curren-
tUser\MY\934a7ac6f8a5d579285a74fa61e19f23ddfe8d7a". Thumbprint
is usually a SHA-1 hex string which you can see in certificate
details. Following store locations are supported: CurrentUser,
LocalMachine, CurrentService, Services, CurrentUserGroupPolicy,
LocalMachineGroupPolicy and LocalMachineEnterprise.
If --cert is provided several times, the last set value is used.
Example:
curl --cert certfile --key keyfile https://example.com
See also --cert-type, --key and --key-type.
--cert-status
(TLS) Verify the status of the server certificate by using the
Certificate Status Request (aka. OCSP stapling) TLS extension.
If this option is enabled and the server sends an invalid (e.g.
expired) response, if the response suggests that the server cer-
tificate has been revoked, or no response at all is received,
the verification fails.
This support is currently only implemented in the OpenSSL and
GnuTLS backends.
Providing --cert-status multiple times has no extra effect.
Disable it again with --no-cert-status.
Example:
curl --cert-status https://example.com
See also --pinnedpubkey.
--cert-type <type>
(TLS) Set type of the provided client certificate. PEM, DER,
ENG, PROV and P12 are recognized types.
The default type depends on the TLS backend and is usually PEM,
however for Secure Transport and Schannel it is P12. If -E,
--cert is a pkcs11: URI then ENG or PROV is the default type
(depending on OpenSSL version).
If --cert-type is provided several times, the last set value is
used.
Example:
curl --cert-type PEM --cert file https://example.com
See also -E, --cert, --key and --key-type.
--ciphers <list>
(TLS) Specify which cipher suites to use in the connection if it
negotiates TLS 1.2 (1.1, 1.0). The list of ciphers suites must
specify valid ciphers. Read up on cipher suite details on this
URL:
https://curl.se/docs/ssl-ciphers.html
If --ciphers is provided several times, the last set value is
used.
Example:
curl --ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256 https://example.com
See also --tls13-ciphers, --proxy-ciphers and --curves.
--compressed
(HTTP) Request a compressed response using one of the algorithms
curl supports, and automatically decompress the content.
Response headers are not modified when saved, so if they are
"interpreted" separately again at a later point they might ap-
pear to be saying that the content is (still) compressed; while
in fact it has already been decompressed.
If this option is used and the server sends an unsupported en-
coding, curl reports an error. This is a request, not an order;
the server may or may not deliver data compressed.
Providing --compressed multiple times has no extra effect. Dis-
able it again with --no-compressed.
Example:
curl --compressed https://example.com
See also --compressed-ssh.
--compressed-ssh
(SCP SFTP) Enable SSH compression. This is a request, not an or-
der; the server may or may not do it.
Providing --compressed-ssh multiple times has no extra effect.
Disable it again with --no-compressed-ssh.
Example:
curl --compressed-ssh sftp://example.com/
See also --compressed.
-K, --config <file>
Specify a text file to read curl arguments from. The command
line arguments found in the text file are used as if they were
provided on the command line.
Options and their parameters must be specified on the same line
in the file, separated by whitespace, colon, or the equals sign.
Long option names can optionally be given in the config file
without the initial double dashes and if so, the colon or equals
characters can be used as separators. If the option is specified
with one or two dashes, there can be no colon or equals charac-
ter between the option and its parameter.
If the parameter contains whitespace or starts with a colon (:)
or equals sign (=), it must be specified enclosed within double
quotes ("like this"). Within double quotes the following escape
sequences are available: \\, \", \t, \n, \r and \v. A backslash
preceding any other letter is ignored.
If the first non-blank column of a config line is a '#' charac-
ter, that line is treated as a comment.
Only write one option per physical line in the config file. A
single line is required to be no more than 10 megabytes (since
8.2.0).
Specify the filename to -K, --config as minus "-" to make curl
read the file from stdin.
Note that to be able to specify a URL in the config file, you
need to specify it using the --url option, and not by simply
writing the URL on its own line. So, it could look similar to
this:
url = "https://curl.se/docs/"
# --- Example file ---
# this is a comment
url = "example.com"
output = "curlhere.html"
user-agent = "superagent/1.0"
# and fetch another URL too
url = "example.com/docs/manpage.html"
-O
referer = "http://nowhereatall.example.com/"
# --- End of example file ---
When curl is invoked, it (unless -q, --disable is used) checks
for a default config file and uses it if found, even when -K,
--config is used. The default config file is checked for in the
following places in this order:
1) "$CURL_HOME/.curlrc"
2) "$XDG_CONFIG_HOME/curlrc" (Added in 7.73.0)
3) "$HOME/.curlrc"
4) Windows: "%USERPROFILE%\.curlrc"
5) Windows: "%APPDATA%\.curlrc"
6) Windows: "%USERPROFILE%\Application Data\.curlrc"
7) Non-Windows: use getpwuid to find the home directory
8) On Windows, if it finds no .curlrc file in the sequence de-
scribed above, it checks for one in the same directory the curl
executable is placed.
On Windows two filenames are checked per location: .curlrc and
_curlrc, preferring the former. Older versions on Windows
checked for _curlrc only.
--config can be used several times in a command line
Example:
curl --config file.txt https://example.com
See also -q, --disable.
--connect-timeout <seconds>
Maximum time in seconds that you allow curl's connection to
take. This only limits the connection phase, so if curl connects
within the given period it continues - if not it exits.
This option accepts decimal values. The decimal value needs to
be provided using a dot (.) as decimal separator - not the local
version even if it might be using another separator.
The connection phase is considered complete when the DNS lookup
and requested TCP, TLS or QUIC handshakes are done.
If --connect-timeout is provided several times, the last set
value is used.
Examples:
curl --connect-timeout 20 https://example.com
curl --connect-timeout 3.14 https://example.com
See also -m, --max-time.
--connect-to <HOST1:PORT1:HOST2:PORT2>
For a request intended for the "HOST1:PORT1" pair, connect to
"HOST2:PORT2" instead. This option is only used to establish the
network connection. It does NOT affect the hostname/port number
that is used for TLS/SSL (e.g. SNI, certificate verification) or
for the application protocols.
"HOST1" and "PORT1" may be empty strings, meaning any host or
any port number. "HOST2" and "PORT2" may also be empty strings,
meaning use the request's original hostname and port number.
A hostname specified to this option is compared as a string, so
it needs to match the name used in the request URL. It can be
either numerical such as "127.0.0.1" or the full host name such
as "example.org".
Example: redirect connects from the example.com hostname to
127.0.0.1 independently of port number:
curl --connect-to example.com::127.0.0.1: https://example.com/
Example: redirect connects from all hostnames to 127.0.0.1 inde-
pendently of port number:
curl --connect-to ::127.0.0.1: http://example.com/
--connect-to can be used several times in a command line
Example:
curl --connect-to example.com:443:example.net:8443 https://example.com
See also --resolve and -H, --header.
-C, --continue-at <offset>
Resume a previous transfer from the given byte offset. The given
offset is the exact number of bytes that are skipped, counting
from the beginning of the source file before it is transferred
to the destination. If used with uploads, the FTP server command
SIZE is not used by curl.
Use "-C -" to instruct curl to automatically find out where/how
to resume the transfer. It then uses the given output/input
files to figure that out.
When using this option for HTTP uploads using POST or PUT, func-
tionality is not guaranteed. The HTTP protocol has no standard
interoperable resume upload and curl uses a set of headers for
this purpose that once proved working for some servers and have
been left for those who find that useful.
This command line option is mutually exclusive with -r, --range:
you can only use one of them for a single transfer.
The --no-clobber and --remove-on-error options cannot be used
together with -C, --continue-at.
If --continue-at is provided several times, the last set value
is used.
Examples:
curl -C - https://example.com
curl -C 400 https://example.com
See also -r, --range.
-b, --cookie <data|filename>
(HTTP) This option has two slightly separate cookie sending
functions.
Either: pass the exact data to send to the HTTP server in the
Cookie header. It is supposedly data previously received from
the server in a "Set-Cookie:" line. The data should be in the
format "NAME1=VALUE1; NAME2=VALUE2". When given a set of spe-
cific cookies, curl populates its cookie header with this con-
tent explicitly in all outgoing request(s). If multiple requests
are done due to authentication, followed redirects or similar,
they all get this cookie header passed on.
Or: If no "=" symbol is used in the argument, it is instead
treated as a filename to read previously stored cookie from.
This option also activates the cookie engine which makes curl
record incoming cookies, which may be handy if you are using
this in combination with the -L, --location option or do multi-
ple URL transfers on the same invoke.
If the filename is a single minus ("-"), curl reads the contents
from stdin. If the filename is an empty string ("") and is the
only cookie input, curl activates the cookie engine without any
cookies.
The file format of the file to read cookies from should be plain
HTTP headers (Set-Cookie style) or the Netscape/Mozilla cookie
file format.
The file specified with -b, --cookie is only used as input. No
cookies are written to that file. To store cookies, use the -c,
--cookie-jar option.
If you use the Set-Cookie file format and do not specify a do-
main then the cookie is not sent since the domain never matches.
To address this, set a domain in Set-Cookie line (doing that in-
cludes subdomains) or preferably: use the Netscape format.
Users often want to both read cookies from a file and write up-
dated cookies back to a file, so using both -b, --cookie and -c,
--cookie-jar in the same command line is common.
If curl is built with PSL (Public Suffix List) support, it de-
tects and discards cookies that are specified for such suffix
domains that should not be allowed to have cookies. If curl is
not built with PSL support, it has no ability to stop super
cookies.
--cookie can be used several times in a command line
Examples:
curl -b "" https://example.com
curl -b cookiefile https://example.com
curl -b cookiefile -c cookiefile https://example.com
curl -b name=Jane https://example.com
See also -c, --cookie-jar and -j, --junk-session-cookies.
-c, --cookie-jar <filename>
(HTTP) Specify to which file you want curl to write all cookies
after a completed operation. curl writes all cookies from its
in-memory cookie storage to the given file at the end of opera-
tions. Even if no cookies are known, a file is created so that
it removes any formerly existing cookies from the file. The file
uses the Netscape cookie file format. If you set the filename to
a single minus, "-", the cookies are written to stdout.
The file specified with -c, --cookie-jar is only used for out-
put. No cookies are read from the file. To read cookies, use the
-b, --cookie option. Both options can specify the same file.
This command line option activates the cookie engine that makes
curl record and use cookies. The -b, --cookie option also acti-
vates it.
If the cookie jar cannot be created or written to, the whole
curl operation does not fail or even report an error clearly.
Using -v, --verbose gets a warning displayed, but that is the
only visible feedback you get about this possibly lethal situa-
tion.
If --cookie-jar is provided several times, the last set value is
used.
Examples:
curl -c store-here.txt https://example.com
curl -c store-here.txt -b read-these https://example.com
See also -b, --cookie and -j, --junk-session-cookies.
--create-dirs
When used in conjunction with the -o, --output option, curl cre-
ates the necessary local directory hierarchy as needed. This op-
tion creates the directories mentioned with the -o, --output op-
tion combined with the path possibly set with --output-dir. If
the combined output filename uses no directory, or if the direc-
tories it mentions already exist, no directories are created.
Created directories are made with mode 0750 on Unix-style file
systems.
To create remote directories when using FTP or SFTP, try
--ftp-create-dirs.
Providing --create-dirs multiple times has no extra effect.
Disable it again with --no-create-dirs.
Example:
curl --create-dirs --output local/dir/file https://example.com
See also --ftp-create-dirs and --output-dir.
--create-file-mode <mode>
(SFTP SCP FILE) When curl is used to create files remotely using
one of the supported protocols, this option allows the user to
set which 'mode' to set on the file at creation time, instead of
the default 0644.
This option takes an octal number as argument.
If --create-file-mode is provided several times, the last set
value is used.
Example:
curl --create-file-mode 0777 -T localfile sftp://example.com/new
Added in 7.75.0. See also --ftp-create-dirs.
--crlf (FTP SMTP) Convert line feeds to carriage return plus line feeds
in upload. Useful for MVS (OS/390).
Providing --crlf multiple times has no extra effect. Disable it
again with --no-crlf.
Example:
curl --crlf -T file ftp://example.com/
See also -B, --use-ascii.
--crlfile <file>
(TLS) Provide a file using PEM format with a Certificate Revoca-
tion List that may specify peer certificates that are to be con-
sidered revoked.
If --crlfile is provided several times, the last set value is
used.
Example:
curl --crlfile rejects.txt https://example.com
See also --cacert and --capath.
--curves <list>
(TLS) Set specific curves to use during SSL session establish-
ment according to RFC 8422, 5.1. Multiple algorithms can be pro-
vided by separating them with ":" (e.g. "X25519:P-521"). The pa-
rameter is available identically in the OpenSSL "s_client" and
"s_server" utilities.
--curves allows a OpenSSL powered curl to make SSL-connections
with exactly the (EC) curve requested by the client, avoiding
nontransparent client/server negotiations.
If this option is set, the default curves list built into
OpenSSL are ignored.
If --curves is provided several times, the last set value is
used.
Example:
curl --curves X25519 https://example.com
Added in 7.73.0. See also --ciphers.
-d, --data <data>
(HTTP MQTT) Send the specified data in a POST request to the
HTTP server, in the same way that a browser does when a user has
filled in an HTML form and presses the submit button. This op-
tion makes curl pass the data to the server using the con-
tent-type application/x-www-form-urlencoded. Compared to -F,
--form.
--data-raw is almost the same but does not have a special inter-
pretation of the @ character. To post data purely binary, you
should instead use the --data-binary option. To URL-encode the
value of a form field you may use --data-urlencode.
If any of these options is used more than once on the same com-
mand line, the data pieces specified are merged with a separat-
ing &-symbol. Thus, using '-d name=daniel -d skill=lousy' would
generate a post chunk that looks like 'name=daniel&skill=lousy'.
If you start the data with the letter @, the rest should be a
filename to read the data from, or - if you want curl to read
the data from stdin. Posting data from a file named 'foobar'
would thus be done with -d, --data @foobar. When -d, --data is
told to read from a file like that, carriage returns, newlines
and null bytes are stripped out. If you do not want the @ char-
acter to have a special interpretation use --data-raw instead.
The data for this option is passed on to the server exactly as
provided on the command line. curl does not convert, change or
improve it. It is up to the user to provide the data in the cor-
rect form.
--data can be used several times in a command line
Examples:
curl -d "name=curl" https://example.com
curl -d "name=curl" -d "tool=cmdline" https://example.com
curl -d @filename https://example.com
This option is mutually exclusive with -F, --form, -I, --head
and -T, --upload-file. See also --data-binary, --data-urlencode
and --data-raw.
--data-ascii <data>
(HTTP) This option is just an alias for -d, --data.
--data-ascii can be used several times in a command line
Example:
curl --data-ascii @file https://example.com
See also --data-binary, --data-raw and --data-urlencode.
--data-binary <data>
(HTTP) Post data exactly as specified with no extra processing
whatsoever.
If you start the data with the letter @, the rest should be a
filename. "@-" makes curl read the data from stdin. Data is
posted in a similar manner as -d, --data does, except that new-
lines and carriage returns are preserved and conversions are
never done.
Like -d, --data the default content-type sent to the server is
application/x-www-form-urlencoded. If you want the data to be
treated as arbitrary binary data by the server then set the con-
tent-type to octet-stream: -H "Content-Type: applica-
tion/octet-stream".
If this option is used several times, the ones following the
first append data as described in -d, --data.
--data-binary can be used several times in a command line
Example:
curl --data-binary @filename https://example.com
See also --data-ascii.
--data-raw <data>
(HTTP) Post data similarly to -d, --data but without the special
interpretation of the @ character.
--data-raw can be used several times in a command line
Examples:
curl --data-raw "hello" https://example.com
curl --data-raw "@at@at@" https://example.com
See also -d, --data.
--data-urlencode <data>
(HTTP) Post data, similar to the other -d, --data options with
the exception that this performs URL-encoding.
To be CGI-compliant, the <data> part should begin with a name
followed by a separator and a content specification. The <data>
part can be passed to curl using one of the following syntaxes:
content
URL-encode the content and pass that on. Just be careful
so that the content does not contain any "=" or "@" sym-
bols, as that makes the syntax match one of the other
cases below.
=content
URL-encode the content and pass that on. The preceding
"=" symbol is not included in the data.
name=content
URL-encode the content part and pass that on. Note that
the name part is expected to be URL-encoded already.
@filename
load data from the given file (including any newlines),
URL-encode that data and pass it on in the POST. Using
"@-" makes curl read the data from stdin.
name@filename
load data from the given file (including any newlines),
URL-encode that data and pass it on in the POST. The name
part gets an equal sign appended, resulting in name=ur-
lencoded-file-content. Note that the name is expected to
be URL-encoded already.
--data-urlencode can be used several times in a command line
Examples:
curl --data-urlencode name=val https://example.com
curl --data-urlencode =encodethis https://example.com
curl --data-urlencode name@file https://example.com
curl --data-urlencode @fileonly https://example.com
See also -d, --data and --data-raw.
--delegation <LEVEL>
(GSS/kerberos) Set LEVEL what curl is allowed to delegate when
it comes to user credentials.
none Do not allow any delegation.
policy Delegates if and only if the OK-AS-DELEGATE flag is set
in the Kerberos service ticket, which is a matter of
realm policy.
always Unconditionally allow the server to delegate.
If --delegation is provided several times, the last set value is
used.
Example:
curl --delegation "none" https://example.com
See also -k, --insecure and --ssl.
--digest
(HTTP) Enable HTTP Digest authentication. This authentication
scheme avoids sending the password over the wire in clear text.
Use this in combination with the normal -u, --user option to set
username and password.
Providing --digest multiple times has no extra effect. Disable
it again with --no-digest.
Example:
curl -u name:password --digest https://example.com
This option is mutually exclusive with --basic, --ntlm and --ne-
gotiate. See also -u, --user, --proxy-digest and --anyauth.
-q, --disable
If used as the first parameter on the command line, the curlrc
config file is not read or used. See the -K, --config for de-
tails on the default config file search path.
Providing --disable multiple times has no extra effect. Disable
it again with --no-disable.
Example:
curl -q https://example.com
See also -K, --config.
--disable-eprt
(FTP) Disable the use of the EPRT and LPRT commands when doing
active FTP transfers. curl normally first attempts to use EPRT
before using PORT, but with this option, it uses PORT right
away. EPRT is an extension to the original FTP protocol, and
does not work on all servers, but enables more functionality in
a better way than the traditional PORT command.
--eprt can be used to explicitly enable EPRT again and --no-eprt
is an alias for --disable-eprt.
If the server is accessed using IPv6, this option has no effect
as EPRT is necessary then.
Disabling EPRT only changes the active behavior. If you want to
switch to passive mode you need to not use -P, --ftp-port or
force it with --ftp-pasv.
Providing --disable-eprt multiple times has no extra effect.
Disable it again with --no-disable-eprt.
Example:
curl --disable-eprt ftp://example.com/
See also --disable-epsv and -P, --ftp-port.
--disable-epsv
(FTP) Disable the use of the EPSV command when doing passive FTP
transfers. curl normally first attempts to use EPSV before PASV,
but with this option, it does not try EPSV.
--epsv can be used to explicitly enable EPSV again and --no-epsv
is an alias for --disable-epsv.
If the server is an IPv6 host, this option has no effect as EPSV
is necessary then.
Disabling EPSV only changes the passive behavior. If you want to
switch to active mode you need to use -P, --ftp-port.
Providing --disable-epsv multiple times has no extra effect.
Disable it again with --no-disable-epsv.
Example:
curl --disable-epsv ftp://example.com/
See also --disable-eprt and -P, --ftp-port.
--disallow-username-in-url
Exit with error if passed a URL containing a username. Probably
most useful when the URL is being provided at runtime or simi-
lar.
Providing --disallow-username-in-url multiple times has no extra
effect. Disable it again with --no-disallow-username-in-url.
Example:
curl --disallow-username-in-url https://example.com
Added in 7.61.0. See also --proto.
--dns-interface <interface>
(DNS) Send outgoing DNS requests through the given interface.
This option is a counterpart to --interface (which does not af-
fect DNS). The supplied string must be an interface name (not an
address).
If --dns-interface is provided several times, the last set value
is used.
Example:
curl --dns-interface eth0 https://example.com
--dns-interface requires that libcurl is built to support c-
ares. See also --dns-ipv4-addr and --dns-ipv6-addr.
--dns-ipv4-addr <address>
(DNS) Bind to a specific IP address when making IPv4 DNS re-
quests, so that the DNS requests originate from this address.
The argument should be a single IPv4 address.
If --dns-ipv4-addr is provided several times, the last set value
is used.
Example:
curl --dns-ipv4-addr 10.1.2.3 https://example.com
--dns-ipv4-addr requires that libcurl is built to support c-
ares. See also --dns-interface and --dns-ipv6-addr.
--dns-ipv6-addr <address>
(DNS) Bind to a specific IP address when making IPv6 DNS re-
quests, so that the DNS requests originate from this address.
The argument should be a single IPv6 address.
If --dns-ipv6-addr is provided several times, the last set value
is used.
Example:
curl --dns-ipv6-addr 2a04:4e42::561 https://example.com
--dns-ipv6-addr requires that libcurl is built to support c-
ares. See also --dns-interface and --dns-ipv4-addr.
--dns-servers <addresses>
(DNS) Set the list of DNS servers to be used instead of the sys-
tem default. The list of IP addresses should be separated with
commas. Port numbers may also optionally be given, appended to
the IP address separated with a colon.
If --dns-servers is provided several times, the last set value
is used.
Examples:
curl --dns-servers 192.168.0.1,192.168.0.2 https://example.com
curl --dns-servers 10.0.0.1:53 https://example.com
--dns-servers requires that libcurl is built to support c-ares.
See also --dns-interface and --dns-ipv4-addr.
--doh-cert-status
Same as --cert-status but used for DoH (DNS-over-HTTPS).
Verify the status of the DoH servers' certificate by using the
Certificate Status Request (aka. OCSP stapling) TLS extension.
If this option is enabled and the DoH server sends an invalid
(e.g. expired) response, if the response suggests that the
server certificate has been revoked, or no response at all is
received, the verification fails.
This support is currently only implemented in the OpenSSL and
GnuTLS backends.
Providing --doh-cert-status multiple times has no extra effect.
Disable it again with --no-doh-cert-status.
Example:
curl --doh-cert-status --doh-url https://doh.example https://example.com
Added in 7.76.0. See also --doh-insecure.
--doh-insecure
By default, every connection curl makes to a DoH server is veri-
fied to be secure before the transfer takes place. This option
tells curl to skip the verification step and proceed without
checking.
WARNING: using this option makes the DoH transfer and name reso-
lution insecure.
This option is equivalent to -k, --insecure and --proxy-insecure
but used for DoH (DNS-over-HTTPS) only.
Providing --doh-insecure multiple times has no extra effect.
Disable it again with --no-doh-insecure.
Example:
curl --doh-insecure --doh-url https://doh.example https://example.com
Added in 7.76.0. See also --doh-url, -k, --insecure and
--proxy-insecure.
--doh-url <URL>
Specify which DNS-over-HTTPS (DoH) server to use to resolve
hostnames, instead of using the default name resolver mechanism.
The URL must be HTTPS.
Some SSL options that you set for your transfer also apply to
DoH since the name lookups take place over SSL. However, the
certificate verification settings are not inherited but are con-
trolled separately via --doh-insecure and --doh-cert-status.
By default, DoH is bypassed when initially looking up DNS
records of the DoH server. You can specify the IP address(es) of
the DoH server with --resolve to avoid this.
This option is unset if an empty string "" is used as the URL.
(Added in 7.85.0)
If --doh-url is provided several times, the last set value is
used.
Examples:
curl --doh-url https://doh.example https://example.com
curl --doh-url https://doh.example --resolve doh.example:443:192.0.2.1 https://example.com
Added in 7.62.0. See also --doh-insecure.
--dump-ca-embed
(TLS) Write the CA bundle embedded in curl to standard output,
then quit.
If curl was not built with a default CA bundle embedded, the
output is empty.
Providing --dump-ca-embed multiple times has no extra effect.
Disable it again with --no-dump-ca-embed.
Example:
curl --dump-ca-embed
Added in 8.10.0. See also --ca-native, --cacert, --capath,
--proxy-ca-native, --proxy-cacert and --proxy-capath.
-D, --dump-header <filename>
(HTTP FTP) Write the received protocol headers to the specified
file. If no headers are received, the use of this option creates
an empty file. Specify "-" as filename (a single minus) to have
it written to stdout.
Starting in curl 8.10.0, specify "%" (a single percent sign) as
filename writes the output to stderr.
When used in FTP, the FTP server response lines are considered
being "headers" and thus are saved there.
Starting in curl 8.11.0, using the --create-dirs option can also
create missing directory components for the path provided in -D,
--dump-header.
Having multiple transfers in one set of operations (i.e. the
URLs in one -:, --next clause), appends them to the same file,
separated by a blank line.
If --dump-header is provided several times, the last set value
is used.
Examples:
curl --dump-header store.txt https://example.com
curl --dump-header - https://example.com -o save
See also -o, --output.
--ech <config>
(HTTPS) Specify how to do ECH (Encrypted Client Hello).
The values allowed for <config> can be:
false Do not attempt ECH. The is the default.
grease Send a GREASE ECH extension
true Attempt ECH if possible, but do not fail if ECH is not
attempted. (The connection fails if ECH is attempted but
fails.)
hard Attempt ECH and fail if that is not possible. ECH only
works with TLS 1.3 and also requires using DoH or provid-
ing an ECHConfigList on the command line.
ecl:<b64val>
A base64 encoded ECHConfigList that is used for ECH.
pn:<name>
A name to use to over-ride the "public_name" field of an
ECHConfigList (only available with OpenSSL TLS support)
Most ECH related errors cause error CURLE_ECH_REQUIRED (101).
If --ech is provided several times, the last set value is used.
Example:
curl --ech true https://example.com
Added in 8.8.0. See also --doh-url.
--egd-file <file>
(TLS) Deprecated option (added in 7.84.0). Prior to that it only
had an effect on curl if built to use old versions of OpenSSL.
Specify the path name to the Entropy Gathering Daemon socket.
The socket is used to seed the random engine for SSL connec-
tions.
If --egd-file is provided several times, the last set value is
used.
Example:
curl --egd-file /random/here https://example.com
See also --random-file.
--engine <name>
(TLS) Select the OpenSSL crypto engine to use for cipher opera-
tions. Use --engine list to print a list of build-time supported
engines. Note that not all (and possibly none) of the engines
may be available at runtime.
If --engine is provided several times, the last set value is
used.
Example:
curl --engine flavor https://example.com
See also --ciphers and --curves.
--etag-compare <file>
(HTTP) Make a conditional HTTP request for the specific ETag
read from the given file by sending a custom If-None-Match
header using the stored ETag.
For correct results, make sure that the specified file contains
only a single line with the desired ETag. A non-existing or
empty file is treated as an empty ETag.
Use the option --etag-save to first save the ETag from a re-
sponse, and then use this option to compare against the saved
ETag in a subsequent request.
Use this option with a single URL only.
If --etag-compare is provided several times, the last set value
is used.
Example:
curl --etag-compare etag.txt https://example.com
Added in 7.68.0. See also --etag-save and -z, --time-cond.
--etag-save <file>
(HTTP) Save an HTTP ETag to the specified file. An ETag is a
caching related header, usually returned in a response. Use this
option with a single URL only.
If no ETag is sent by the server, an empty file is created.
In many situations you want to use an existing etag in the re-
quest to avoid downloading the same resource again but also save
the new etag if it has indeed changed, by using both etag op-
tions --etag-save and --etag-compare with the same filename, in
the same command line.
Starting in curl 8.12.0, using the --create-dirs option can also
create missing directory components for the path provided in
--etag-save.
If --etag-save is provided several times, the last set value is
used.
Example:
curl --etag-save storetag.txt https://example.com
Added in 7.68.0. See also --etag-compare.
--expect100-timeout <seconds>
(HTTP) Maximum time in seconds that you allow curl to wait for a
100-continue response when curl emits an Expects: 100-continue
header in its request. By default curl waits one second. This
option accepts decimal values. When curl stops waiting, it con-
tinues as if a response was received.
The decimal value needs to be provided using a dot (".") as dec-
imal separator - not the local version even if it might be using
another separator.
If --expect100-timeout is provided several times, the last set
value is used.
Example:
curl --expect100-timeout 2.5 -T file https://example.com
See also --connect-timeout.
-f, --fail
(HTTP) Fail with error code 22 and with no response body output
at all for HTTP transfers returning HTTP response codes at 400
or greater.
In normal cases when an HTTP server fails to deliver a document,
it returns a body of text stating so (which often also describes
why and more) and a 4xx HTTP response code. This command line
option prevents curl from outputting that data and instead re-
turns error 22 early. By default, curl does not consider HTTP
response codes to indicate failure.
To get both the error code and also save the content, use
--fail-with-body instead.
This method is not fail-safe and there are occasions where
non-successful response codes slip through, especially when au-
thentication is involved (response codes 401 and 407).
Providing --fail multiple times has no extra effect. Disable it
again with --no-fail.
Example:
curl --fail https://example.com
This option is mutually exclusive with --fail-with-body. See
also --fail-with-body and --fail-early.
--fail-early
Fail and exit on the first detected transfer error.
When curl is used to do multiple transfers on the command line,
it attempts to operate on each given URL, one by one. By de-
fault, it ignores errors if there are more URLs given and the
last URL's success determines the error code curl returns. Early
failures are "hidden" by subsequent successful transfers.
Using this option, curl instead returns an error on the first
transfer that fails, independent of the amount of URLs that are
given on the command line. This way, no transfer failures go un-
detected by scripts and similar.
This option does not imply -f, --fail, which causes transfers to
fail due to the server's HTTP status code. You can combine the
two options, however note -f, --fail is not global and is there-
fore contained by -:, --next.
This option is global and does not need to be specified for each
use of --next.
Providing --fail-early multiple times has no extra effect. Dis-
able it again with --no-fail-early.
Example:
curl --fail-early https://example.com https://two.example
See also -f, --fail and --fail-with-body.
--fail-with-body
(HTTP) Return an error on server errors where the HTTP response
code is 400 or greater). In normal cases when an HTTP server
fails to deliver a document, it returns an HTML document stating
so (which often also describes why and more). This option al-
lows curl to output and save that content but also to return er-
ror 22.
This is an alternative option to -f, --fail which makes curl
fail for the same circumstances but without saving the content.
Providing --fail-with-body multiple times has no extra effect.
Disable it again with --no-fail-with-body.
Example:
curl --fail-with-body https://example.com
This option is mutually exclusive with -f, --fail. Added in
7.76.0. See also -f, --fail and --fail-early.
--false-start
(TLS) Use false start during the TLS handshake. False start is a
mode where a TLS client starts sending application data before
verifying the server's Finished message, thus saving a round
trip when performing a full handshake.
This functionality is currently only implemented in the Secure
Transport (on iOS 7.0 or later, or macOS 10.9 or later) backend.
Providing --false-start multiple times has no extra effect.
Disable it again with --no-false-start.
Example:
curl --false-start https://example.com
See also --tcp-fastopen.
-F, --form <name=content>
(HTTP SMTP IMAP) For the HTTP protocol family, emulate a
filled-in form in which a user has pressed the submit button.
This makes curl POST data using the Content-Type multi-
part/form-data according to RFC 2388.
For SMTP and IMAP protocols, this composes a multipart mail mes-
sage to transmit.
This enables uploading of binary files etc. To force the 'con-
tent' part to be a file, prefix the filename with an @ sign. To
just get the content part from a file, prefix the filename with
the symbol <. The difference between @ and < is then that @
makes a file get attached in the post as a file upload, while
the < makes a text field and just gets the contents for that
text field from a file.
Read content from stdin instead of a file by using a single "-"
as filename. This goes for both @ and < constructs. When stdin
is used, the contents is buffered in memory first by curl to de-
termine its size and allow a possible resend. Defining a part's
data from a named non-regular file (such as a named pipe or sim-
ilar) is not subject to buffering and is instead read at trans-
mission time; since the full size is unknown before the transfer
starts, such data is sent as chunks by HTTP and rejected by
IMAP.
Example: send an image to an HTTP server, where 'profile' is the
name of the form-field to which the file portrait.jpg is the in-
put:
curl -F profile=@portrait.jpg https://example.com/upload.cgi
Example: send your name and shoe size in two text fields to the
server:
curl -F name=John -F shoesize=11 https://example.com/
Example: send your essay in a text field to the server. Send it
as a plain text field, but get the contents for it from a local
file:
curl -F "story=<hugefile.txt" https://example.com/
You can also instruct curl what Content-Type to use by using
"type=", in a manner similar to:
curl -F "web=@index.html;type=text/html" example.com
or
curl -F "name=daniel;type=text/foo" example.com
You can also explicitly change the name field of a file upload
part by setting filename=, like this:
curl -F "file=@localfile;filename=nameinpost" example.com
If filename/path contains ',' or ';', it must be quoted by dou-
ble-quotes like:
curl -F "file=@\"local,file\";filename=\"name;in;post\"" \
https://example.com
or
curl -F 'file=@"local,file";filename="name;in;post"' \
https://example.com
Note that if a filename/path is quoted by double-quotes, any
double-quote or backslash within the filename must be escaped by
backslash.
Quoting must also be applied to non-file data if it contains
semicolons, leading/trailing spaces or leading double quotes:
curl -F 'colors="red; green; blue";type=text/x-myapp' \
https://example.com
You can add custom headers to the field by setting headers=,
like
curl -F "submit=OK;headers=\"X-submit-type: OK\"" example.com
or
curl -F "submit=OK;headers=@headerfile" example.com
The headers= keyword may appear more than once and above notes
about quoting apply. When headers are read from a file, empty
lines and lines starting with '#' are ignored; each header can
be folded by splitting between two words and starting the con-
tinuation line with a space; embedded carriage-returns and
trailing spaces are stripped. Here is an example of a header
file contents:
# This file contains two headers.
X-header-1: this is a header
# The following header is folded.
X-header-2: this is
another header
To support sending multipart mail messages, the syntax is ex-
tended as follows:
- name can be omitted: the equal sign is the first character of
the argument,
- if data starts with '(', this signals to start a new multi-
part: it can be followed by a content type specification.
- a multipart can be terminated with a '=)' argument.
Example: the following command sends an SMTP mime email consist-
ing in an inline part in two alternative formats: plain text and
HTML. It attaches a text file:
curl -F '=(;type=multipart/alternative' \
-F '=plain text message' \
-F '= <body>HTML message</body>;type=text/html' \
-F '=)' -F '=@textfile.txt' ... smtp://example.com
Data can be encoded for transfer using encoder=. Available en-
codings are binary and 8bit that do nothing else than adding the
corresponding Content-Transfer-Encoding header, 7bit that only
rejects 8-bit characters with a transfer error, quoted-printable
and base64 that encodes data according to the corresponding
schemes, limiting lines length to 76 characters.
Example: send multipart mail with a quoted-printable text mes-
sage and a base64 attached file:
curl -F '=text message;encoder=quoted-printable' \
-F '=@localfile;encoder=base64' ... smtp://example.com
See further examples and details in the MANUAL.
--form can be used several times in a command line
Example:
curl --form "name=curl" --form "file=@loadthis" https://example.com
This option is mutually exclusive with -d, --data, -I, --head
and -T, --upload-file. See also -d, --data, --form-string and
--form-escape.
--form-escape
(HTTP imap smtp) Pass on names of multipart form fields and
files using backslash-escaping instead of percent-encoding.
If --form-escape is provided several times, the last set value
is used.
Example:
curl --form-escape -F 'field\name=curl' -F 'file=@load"this' https://example.com
Added in 7.81.0. See also -F, --form.
--form-string <name=string>
(HTTP SMTP IMAP) Similar to -F, --form except that the value
string for the named parameter is used literally. Leading @ and
< characters, and the ";type=" string in the value have no spe-
cial meaning. Use this in preference to -F, --form if there is
any possibility that the string value may accidentally trigger
the @ or < features of -F, --form.
--form-string can be used several times in a command line
Example:
curl --form-string "name=data" https://example.com
See also -F, --form.
--ftp-account <data>
(FTP) When an FTP server asks for "account data" after username
and password has been provided, this data is sent off using the
ACCT command.
If --ftp-account is provided several times, the last set value
is used.
Example:
curl --ftp-account "mr.robot" ftp://example.com/
See also -u, --user.
--ftp-alternative-to-user <command>
(FTP) If authenticating with the USER and PASS commands fails,
send this command. When connecting to Tumbleweed's Secure
Transport server over FTPS using a client certificate, using
"SITE AUTH" tells the server to retrieve the username from the
certificate.
If --ftp-alternative-to-user is provided several times, the last
set value is used.
Example:
curl --ftp-alternative-to-user "U53r" ftp://example.com
See also --ftp-account and -u, --user.
--ftp-create-dirs
(FTP SFTP) When an FTP or SFTP URL/operation uses a path that
does not currently exist on the server, the standard behavior of
curl is to fail. Using this option, curl instead attempts to
create missing directories.
Providing --ftp-create-dirs multiple times has no extra effect.
Disable it again with --no-ftp-create-dirs.
Example:
curl --ftp-create-dirs -T file ftp://example.com/remote/path/file
See also --create-dirs.
--ftp-method <method>
(FTP) Control what method curl should use to reach a file on an
FTP(S) server. The method argument should be one of the follow-
ing alternatives:
multicwd
Do a single CWD operation for each path part in the given
URL. For deep hierarchies this means many commands. This
is how RFC 1738 says it should be done. This is the de-
fault but the slowest behavior.
nocwd Do no CWD at all. curl does SIZE, RETR, STOR etc and
gives the full path to the server for each of these com-
mands. This is the fastest behavior.
singlecwd
Do one CWD with the full target directory and then oper-
ate on the file "normally" (like in the multicwd case).
This is somewhat more standards compliant than "nocwd"
but without the full penalty of "multicwd".
If --ftp-method is provided several times, the last set value is
used.
Examples:
curl --ftp-method multicwd ftp://example.com/dir1/dir2/file
curl --ftp-method nocwd ftp://example.com/dir1/dir2/file
curl --ftp-method singlecwd ftp://example.com/dir1/dir2/file
See also -l, --list-only.
--ftp-pasv
(FTP) Use passive mode for the data connection. Passive is the
internal default behavior, but using this option can be used to
override a previous -P, --ftp-port option.
Reversing an enforced passive really is not doable but you must
then instead enforce the correct -P, --ftp-port again.
Passive mode means that curl tries the EPSV command first and
then PASV, unless --disable-epsv is used.
Providing --ftp-pasv multiple times has no extra effect.
Example:
curl --ftp-pasv ftp://example.com/
This option is mutually exclusive with -P, --ftp-port. See also
--disable-epsv.
-P, --ftp-port <address>
(FTP) Reverse the default initiator/listener roles when connect-
ing with FTP. This option makes curl use active mode. curl then
commands the server to connect back to the client's specified
address and port, while passive mode asks the server to setup an
IP address and port for it to connect to. <address> should be
one of:
interface
e.g. eth0 to specify which interface's IP address you
want to use (Unix only)
IP address
e.g. 192.168.10.1 to specify the exact IP address
hostname
e.g. my.host.domain to specify the machine
- make curl pick the same IP address that is already used
for the control connection. This is the recommended
choice.
Disable the use of PORT with --ftp-pasv. Disable the attempt to
use the EPRT command instead of PORT by using --disable-eprt.
EPRT is really PORT++.
You can also append ":[start]-[end]" to the right of the ad-
dress, to tell curl what TCP port range to use. That means you
specify a port range, from a lower to a higher number. A single
number works as well, but do note that it increases the risk of
failure since the port may not be available.
If --ftp-port is provided several times, the last set value is
used.
Examples:
curl -P - ftp:/example.com
curl -P eth0 ftp:/example.com
curl -P 192.168.0.2 ftp:/example.com
See also --ftp-pasv and --disable-eprt.
--ftp-pret
(FTP) Send a PRET command before PASV (and EPSV). Certain FTP
servers, mainly drftpd, require this non-standard command for
directory listings as well as up and downloads in PASV mode.
Providing --ftp-pret multiple times has no extra effect. Dis-
able it again with --no-ftp-pret.
Example:
curl --ftp-pret ftp://example.com/
See also -P, --ftp-port and --ftp-pasv.
--ftp-skip-pasv-ip
(FTP) Do not use the IP address the server suggests in its re-
sponse to curl's PASV command when curl connects the data con-
nection. Instead curl reuses the same IP address it already uses
for the control connection.
This option is enabled by default (added in 7.74.0).
This option has no effect if PORT, EPRT or EPSV is used instead
of PASV.
Providing --ftp-skip-pasv-ip multiple times has no extra effect.
Disable it again with --no-ftp-skip-pasv-ip.
Example:
curl --ftp-skip-pasv-ip ftp://example.com/
See also --ftp-pasv.
--ftp-ssl-ccc
(FTP) Use CCC (Clear Command Channel) Shuts down the SSL/TLS
layer after authenticating. The rest of the control channel com-
munication is unencrypted. This allows NAT routers to follow the
FTP transaction. The default mode is passive.
Providing --ftp-ssl-ccc multiple times has no extra effect.
Disable it again with --no-ftp-ssl-ccc.
Example:
curl --ftp-ssl-ccc ftps://example.com/
See also --ssl and --ftp-ssl-ccc-mode.
--ftp-ssl-ccc-mode <active/passive>
(FTP) Set the CCC mode. The passive mode does not initiate the
shutdown, but instead waits for the server to do it, and does
not reply to the shutdown from the server. The active mode ini-
tiates the shutdown and waits for a reply from the server.
Providing --ftp-ssl-ccc-mode multiple times has no extra effect.
Disable it again with --no-ftp-ssl-ccc-mode.
Example:
curl --ftp-ssl-ccc-mode active --ftp-ssl-ccc ftps://example.com/
See also --ftp-ssl-ccc.
--ftp-ssl-control
(FTP) Require SSL/TLS for the FTP login, clear for transfer. Al-
lows secure authentication, but non-encrypted data transfers for
efficiency. Fails the transfer if the server does not support
SSL/TLS.
Providing --ftp-ssl-control multiple times has no extra effect.
Disable it again with --no-ftp-ssl-control.
Example:
curl --ftp-ssl-control ftp://example.com
See also --ssl.
-G, --get
(HTTP) When used, this option makes all data specified with -d,
--data, --data-binary or --data-urlencode to be used in an HTTP
GET request instead of the POST request that otherwise would be
used. curl appends the provided data to the URL as a query
string.
If used in combination with -I, --head, the POST data is instead
appended to the URL with a HEAD request.
Providing --get multiple times has no extra effect. Disable it
again with --no-get.
Examples:
curl --get https://example.com
curl --get -d "tool=curl" -d "age=old" https://example.com
curl --get -I -d "tool=curl" https://example.com
See also -d, --data and -X, --request.
-g, --globoff
Switch off the URL globbing function. When you set this option,
you can specify URLs that contain the letters {}[] without hav-
ing curl itself interpret them. Note that these letters are not
normal legal URL contents but they should be encoded according
to the URI standard.
Providing --globoff multiple times has no extra effect. Disable
it again with --no-globoff.
Example:
curl -g "https://example.com/{[]}}}}"
See also -K, --config and -q, --disable.
--happy-eyeballs-timeout-ms <ms>
Set the timeout for Happy Eyeballs.
Happy Eyeballs is an algorithm that attempts to connect to both
IPv4 and IPv6 addresses for dual-stack hosts, giving IPv6 a
head-start of the specified number of milliseconds. If the IPv6
address cannot be connected to within that time, then a connec-
tion attempt is made to the IPv4 address in parallel. The first
connection to be established is the one that is used.
The range of suggested useful values is limited. Happy Eyeballs
RFC 6555 says "It is RECOMMENDED that connection attempts be
paced 150-250 ms apart to balance human factors against network
load." libcurl currently defaults to 200 ms. Firefox and Chrome
currently default to 300 ms.
If --happy-eyeballs-timeout-ms is provided several times, the
last set value is used.
Example:
curl --happy-eyeballs-timeout-ms 500 https://example.com
See also -m, --max-time and --connect-timeout.
--haproxy-clientip <ip>
(HTTP) Set a client IP in HAProxy PROXY protocol v1 header at
the beginning of the connection.
For valid requests, IPv4 addresses must be indicated as a series
of exactly 4 integers in the range [0..255] inclusive written in
decimal representation separated by exactly one dot between each
other. Heading zeroes are not permitted in front of numbers in
order to avoid any possible confusion with octal numbers. IPv6
addresses must be indicated as series of 4 hexadecimal digits
(upper or lower case) delimited by colons between each other,
with the acceptance of one double colon sequence to replace the
largest acceptable range of consecutive zeroes. The total number
of decoded bits must be exactly 128.
Otherwise, any string can be accepted for the client IP and get
sent.
It replaces --haproxy-protocol if used, it is not necessary to
specify both flags.
If --haproxy-clientip is provided several times, the last set
value is used.
Example:
curl --haproxy-clientip $IP
Added in 8.2.0. See also -x, --proxy.
--haproxy-protocol
(HTTP) Send a HAProxy PROXY protocol v1 header at the beginning
of the connection. This is used by some load balancers and re-
verse proxies to indicate the client's true IP address and port.
This option is primarily useful when sending test requests to a
service that expects this header.
Providing --haproxy-protocol multiple times has no extra effect.
Disable it again with --no-haproxy-protocol.
Example:
curl --haproxy-protocol https://example.com
Added in 7.60.0. See also -x, --proxy.
-I, --head
(HTTP FTP FILE) Fetch the headers only. HTTP-servers feature the
command HEAD which this uses to get nothing but the header of a
document. When used on an FTP or FILE URL, curl displays the
file size and last modification time only.
Providing --head multiple times has no extra effect. Disable it
again with --no-head.
Example:
curl -I https://example.com
See also -G, --get, -v, --verbose and --trace-ascii.
-H, --header <header/@file>
(HTTP IMAP SMTP) Extra header to include in information sent.
When used within an HTTP request, it is added to the regular re-
quest headers.
For an IMAP or SMTP MIME uploaded mail built with -F, --form op-
tions, it is prepended to the resulting MIME document, effec-
tively including it at the mail global level. It does not affect
raw uploaded mails.
You may specify any number of extra headers. Note that if you
should add a custom header that has the same name as one of the
internal ones curl would use, your externally set header is used
instead of the internal one. This allows you to make even trick-
ier stuff than curl would normally do. You should not replace
internally set headers without knowing perfectly well what you
are doing. Remove an internal header by giving a replacement
without content on the right side of the colon, as in: -H
"Host:". If you send the custom header with no-value then its
header must be terminated with a semicolon, such as -H "X-Cus-
tom-Header;" to send "X-Custom-Header:".
curl makes sure that each header you add/replace is sent with
the proper end-of-line marker, you should thus not add that as a
part of the header content: do not add newlines or carriage re-
turns, they only mess things up for you. curl passes on the ver-
batim string you give it without any filter or other safe
guards. That includes white space and control characters.
This option can take an argument in @filename style, which then
adds a header for each line in the input file. Using @- makes
curl read the header file from stdin.
Please note that most anti-spam utilities check the presence and
value of several MIME mail headers: these are "From:", "To:",
"Date:" and "Subject:" among others and should be added with
this option.
You need --proxy-header to send custom headers intended for an
HTTP proxy.
Passing on a "Transfer-Encoding: chunked" header when doing an
HTTP request with a request body, makes curl send the data using
chunked encoding.
WARNING: headers set with this option are set in all HTTP re-
quests - even after redirects are followed, like when told with
-L, --location. This can lead to the header being sent to other
hosts than the original host, so sensitive headers should be
used with caution combined with following redirects.
"Authorization:" and "Cookie:" headers are explicitly not passed
on in HTTP requests when following redirects to other origins,
unless --location-trusted is used.
--header can be used several times in a command line
Examples:
curl -H "X-First-Name: Joe" https://example.com
curl -H "User-Agent: yes-please/2000" https://example.com
curl -H "Host:" https://example.com
curl -H @headers.txt https://example.com
See also -A, --user-agent and -e, --referer.
-h, --help <subject>
Usage help. Provide help for the subject given as an optional
argument.
If no argument is provided, curl displays the most important
command line arguments.
The argument can either be a category or a command line option.
When a category is provided, curl shows all command line options
within the given category. Specify category "all" to list all
available options.
If "category" is specified, curl displays all available help
categories.
If the provided subject is instead an existing command line op-
tion, specified either in its short form with a single dash and
a single letter, or in the long form with two dashes and a
longer name, curl displays a help text for that option in the
terminal.
The help output is extensive for some options.
If the provided command line option is not known, curl says so.
Examples:
curl --help all
curl --help --insecure
curl --help -f
See also -v, --verbose.
--hostpubmd5 <md5>
(SFTP SCP) Pass a string containing 32 hexadecimal digits. The
string should be the 128 bit MD5 checksum of the remote host's
public key, curl refuses the connection with the host unless the
checksums match.
If --hostpubmd5 is provided several times, the last set value is
used.
Example:
curl --hostpubmd5 e5c1c49020640a5ab0f2034854c321a8 sftp://example.com/
See also --hostpubsha256.
--hostpubsha256 <sha256>
(SFTP SCP) Pass a string containing a Base64-encoded SHA256 hash
of the remote host's public key. curl refuses the connection
with the host unless the hashes match.
This feature requires libcurl to be built with libssh2 and does
not work with other SSH backends.
If --hostpubsha256 is provided several times, the last set value
is used.
Example:
curl --hostpubsha256 NDVkMTQxMGQ1ODdmMjQ3MjczYjAyOTY5MmRkMjVmNDQ= sftp://example.com/
Added in 7.80.0. See also --hostpubmd5.
--hsts <filename>
(HTTPS) Enable HSTS for the transfer. If the filename points to
an existing HSTS cache file, that is used. After a completed
transfer, the cache is saved to the filename again if it has
been modified.
If curl is told to use HTTP:// for a transfer involving a host-
name that exists in the HSTS cache, it upgrades the transfer to
use HTTPS. Each HSTS cache entry has an individual lifetime af-
ter which the upgrade is no longer performed.
Specify a "" filename (zero length) to avoid loading/saving and
make curl just handle HSTS in memory.
If this option is used several times, curl loads contents from
all the files but the last one is used for saving.
--hsts can be used several times in a command line
Example:
curl --hsts cache.txt https://example.com
Added in 7.74.0. See also --proto.
--http0.9
(HTTP) Accept an HTTP version 0.9 response.
HTTP/0.9 is a response without headers and therefore you can
also connect with this to non-HTTP servers and still get a re-
sponse since curl simply transparently downgrades - if allowed.
HTTP/0.9 is disabled by default (added in 7.66.0)
Providing --http0.9 multiple times has no extra effect. Disable
it again with --no-http0.9.
Example:
curl --http0.9 https://example.com
Added in 7.64.0. See also --http1.1, --http2 and --http3.
-0, --http1.0
(HTTP) Use HTTP version 1.0 instead of using its internally pre-
ferred HTTP version.
Providing --http1.0 multiple times has no extra effect.
Example:
curl --http1.0 https://example.com
This option is mutually exclusive with --http1.1, --http2,
--http2-prior-knowledge and --http3. See also --http0.9 and
--http1.1.
--http1.1
(HTTP) Use HTTP version 1.1. This is the default with HTTP://
URLs.
Providing --http1.1 multiple times has no extra effect.
Example:
curl --http1.1 https://example.com
This option is mutually exclusive with --http1.0, --http2,
--http2-prior-knowledge and --http3. See also --http1.0 and
--http0.9.
--http2
(HTTP) Use HTTP/2.
For HTTPS, this means curl negotiates HTTP/2 in the TLS hand-
shake. curl does this by default.
For HTTP, this means curl attempts to upgrade the request to
HTTP/2 using the Upgrade: request header.
When curl uses HTTP/2 over HTTPS, it does not itself insist on
TLS 1.2 or higher even though that is required by the specifica-
tion. A user can add this version requirement with --tlsv1.2.
Providing --http2 multiple times has no extra effect.
Example:
curl --http2 https://example.com
--http2 requires that libcurl is built to support HTTP/2. This
option is mutually exclusive with --http1.1, --http1.0,
--http2-prior-knowledge and --http3. See also --http1.1,
--http3 and --no-alpn.
--http2-prior-knowledge
(HTTP) Issue a non-TLS HTTP request using HTTP/2 directly with-
out HTTP/1.1 Upgrade. It requires prior knowledge that the
server supports HTTP/2 straight away. HTTPS requests still do
HTTP/2 the standard way with negotiated protocol versions in the
TLS handshake.
Since 8.10.0 if this option is set for an HTTPS request then the
application layer protocol version (ALPN) offered to the server
is only HTTP/2. Prior to that both HTTP/1.1 and HTTP/2 were of-
fered.
Providing --http2-prior-knowledge multiple times has no extra
effect. Disable it again with --no-http2-prior-knowledge.
Example:
curl --http2-prior-knowledge https://example.com
--http2-prior-knowledge requires that libcurl is built to sup-
port HTTP/2. This option is mutually exclusive with --http1.1,
--http1.0, --http2 and --http3. See also --http2 and --http3.
--http3
(HTTP) Attempt HTTP/3 to the host in the URL, but fallback to
earlier HTTP versions if the HTTP/3 connection establishment
fails or is slow. HTTP/3 is only available for HTTPS and not for
HTTP URLs.
This option allows a user to avoid using the Alt-Svc method of
upgrading to HTTP/3 when you know or suspect that the target
speaks HTTP/3 on the given host and port.
When asked to use HTTP/3, curl issues a separate attempt to use
older HTTP versions with a slight delay, so if the HTTP/3 trans-
fer fails or is slow, curl still tries to proceed with an older
HTTP version. The fallback performs the regular negotiation be-
tween HTTP/1 and HTTP/2.
Use --http3-only for similar functionality without a fallback.
Providing --http3 multiple times has no extra effect.
Example:
curl --http3 https://example.com
--http3 requires that libcurl is built to support HTTP/3. This
option is mutually exclusive with --http1.1, --http1.0, --http2,
--http2-prior-knowledge and --http3-only. Added in 7.66.0. See
also --http1.1 and --http2.
--http3-only
(HTTP) Instruct curl to use HTTP/3 to the host in the URL, with
no fallback to earlier HTTP versions. HTTP/3 can only be used
for HTTPS and not for HTTP URLs. For HTTP, this option triggers
an error.
This option allows a user to avoid using the Alt-Svc method of
upgrading to HTTP/3 when you know that the target speaks HTTP/3
on the given host and port.
This option makes curl fail if a QUIC connection cannot be es-
tablished, it does not attempt any other HTTP versions on its
own. Use --http3 for similar functionality with a fallback.
Providing --http3-only multiple times has no extra effect.
Example:
curl --http3-only https://example.com
--http3-only requires that libcurl is built to support HTTP/3.
This option is mutually exclusive with --http1.1, --http1.0,
--http2, --http2-prior-knowledge and --http3. Added in 7.88.0.
See also --http1.1, --http2 and --http3.
--ignore-content-length
(FTP HTTP) For HTTP, ignore the Content-Length header. This is
particularly useful for servers running Apache 1.x, which re-
ports incorrect Content-Length for files larger than 2 giga-
bytes.
For FTP, this makes curl skip the SIZE command to figure out the
size before downloading a file.
Providing --ignore-content-length multiple times has no extra
effect. Disable it again with --no-ignore-content-length.
Example:
curl --ignore-content-length https://example.com
See also --ftp-skip-pasv-ip.
-k, --insecure
(TLS SFTP SCP) By default, every secure connection curl makes is
verified to be secure before the transfer takes place. This op-
tion makes curl skip the verification step and proceed without
checking.
When this option is not used for protocols using TLS, curl veri-
fies the server's TLS certificate before it continues: that the
certificate contains the right name which matches the hostname
used in the URL and that the certificate has been signed by a CA
certificate present in the cert store. See this online resource
for further details: https://curl.se/docs/sslcerts.html
For SFTP and SCP, this option makes curl skip the known_hosts
verification. known_hosts is a file normally stored in the
user's home directory in the ".ssh" subdirectory, which contains
hostnames and their public keys.
WARNING: using this option makes the transfer insecure.
When curl uses secure protocols it trusts responses and allows
for example HSTS and Alt-Svc information to be stored and used
subsequently. Using -k, --insecure can make curl trust and use
such information from malicious servers.
Providing --insecure multiple times has no extra effect. Dis-
able it again with --no-insecure.
Example:
curl --insecure https://example.com
See also --proxy-insecure, --cacert and --capath.
--interface <name>
Perform the operation using a specified interface. You can enter
interface name, IP address or hostname. If you prefer to be spe-
cific, you can use the following special syntax:
if!<name>
Interface name. If the provided name does not match an
existing interface, curl returns with error 45.
host!<name>
IP address or hostname.
ifhost!<interface>!<host>
Interface name and IP address or hostname. This syntax
requires libcurl 8.9.0 or later.
If the provided name does not match an existing inter-
face, curl returns with error 45.
curl does not support using network interface names for this op-
tion on Windows.
That name resolve operation if a hostname is provided does not
use DNS-over-HTTPS even if --doh-url is set.
On Linux this option can be used to specify a VRF (Virtual Rout-
ing and Forwarding) device, but the binary then needs to either
have the CAP_NET_RAW capability set or to be run as root.
If --interface is provided several times, the last set value is
used.
Examples:
curl --interface eth0 https://example.com
curl --interface "host!10.0.0.1" https://example.com
curl --interface "if!enp3s0" https://example.com
See also --dns-interface.
--ip-tos <string>
(All) Set Type of Service (TOS) for IPv4 or Traffic Class for
IPv6.
The values allowed for <string> can be a numeric value between 1
and 255 or one of the following:
CS0, CS1, CS2, CS3, CS4, CS5, CS6, CS7, AF11, AF12, AF13, AF21,
AF22, AF23, AF31, AF32, AF33, AF41, AF42, AF43, EF, VOICE-ADMIT,
ECT1, ECT0, CE, LE, LOWCOST, LOWDELAY, THROUGHPUT, RELIABILITY,
MINCOST
If --ip-tos is provided several times, the last set value is
used.
Example:
curl --ip-tos CS5 https://example.com
Added in 8.9.0. See also --tcp-nodelay and --vlan-priority.
--ipfs-gateway <URL>
(IPFS) Specify which gateway to use for IPFS and IPNS URLs. Not
specifying this instead makes curl check if the IPFS_GATEWAY en-
vironment variable is set, or if a "~/.ipfs/gateway" file hold-
ing the gateway URL exists.
If you run a local IPFS node, this gateway is by default avail-
able under "http://localhost:8080". A full example URL would
look like:
curl --ipfs-gateway http://localhost:8080 \
ipfs://bafybeigagd5nmnn2iys2f3
There are many public IPFS gateways. See for example:
https://ipfs.github.io/public-gateway-checker/
If you opt to go for a remote gateway you need to be aware that
you completely trust the gateway. This might be fine in local
gateways that you host yourself. With remote gateways there
could potentially be malicious actors returning you data that
does not match the request you made, inspect or even interfere
with the request. You may not notice this when using curl. A
mitigation could be to go for a "trustless" gateway. This means
you locally verify the data. Consult the docs page on trusted vs
trustless: https://docs.ipfs.tech/reference/http/gate-
way/#trusted-vs-trustless
If --ipfs-gateway is provided several times, the last set value
is used.
Example:
curl --ipfs-gateway https://example.com ipfs://
Added in 8.4.0. See also -h, --help and -M, --manual.
-4, --ipv4
Use IPv4 addresses only when resolving hostnames, and not for
example try IPv6.
Providing --ipv4 multiple times has no extra effect.
Example:
curl --ipv4 https://example.com
This option is mutually exclusive with -6, --ipv6. See also
--http1.1 and --http2.
-6, --ipv6
Use IPv6 addresses only when resolving hostnames, and not for
example try IPv4.
Your resolver may respond to an IPv6-only resolve request by re-
turning IPv6 addresses that contain "mapped" IPv4 addresses for
compatibility purposes. macOS is known to do this.
Providing --ipv6 multiple times has no extra effect.
Example:
curl --ipv6 https://example.com
This option is mutually exclusive with -4, --ipv4. See also
--http1.1 and --http2.
--json <data>
(HTTP) Send the specified JSON data in a POST request to the
HTTP server. --json works as a shortcut for passing on these
three options:
--data-binary [arg]
--header "Content-Type: application/json"
--header "Accept: application/json"
There is no verification that the passed in data is actual JSON
or that the syntax is correct.
If you start the data with the letter @, the rest should be a
filename to read the data from, or a single dash (-) if you want
curl to read the data from stdin. Posting data from a file named
'foobar' would thus be done with --json @foobar and to instead
read the data from stdin, use --json @-.
If this option is used more than once on the same command line,
the additional data pieces are concatenated to the previous be-
fore sending.
The headers this option sets can be overridden with -H, --header
as usual.
--json can be used several times in a command line
Examples:
curl --json '{ "drink": "coffe" }' https://example.com
curl --json '{ "drink":' --json ' "coffe" }' https://example.com
curl --json @prepared https://example.com
curl --json @- https://example.com < json.txt
This option is mutually exclusive with -F, --form, -I, --head
and -T, --upload-file. Added in 7.82.0. See also --data-binary
and --data-raw.
-j, --junk-session-cookies
(HTTP) When curl is told to read cookies from a given file, this
option makes it discard all "session cookies". This has the same
effect as if a new session is started. Typical browsers discard
session cookies when they are closed down.
Providing --junk-session-cookies multiple times has no extra ef-
fect. Disable it again with --no-junk-session-cookies.
Example:
curl --junk-session-cookies -b cookies.txt https://example.com
See also -b, --cookie and -c, --cookie-jar.
--keepalive-cnt <integer>
Set the maximum number of keepalive probes TCP should send but
get no response before dropping the connection. This option is
usually used in conjunction with --keepalive-time.
This option is supported on Linux, *BSD/macOS, Windows
>=10.0.16299, Solaris 11.4, and recent AIX, HP-UX and more. This
option has no effect if --no-keepalive is used.
If unspecified, the option defaults to 9.
If --keepalive-cnt is provided several times, the last set value
is used.
Example:
curl --keepalive-cnt 3 https://example.com
Added in 8.9.0. See also --keepalive-time and --no-keepalive.
--keepalive-time <seconds>
Set the time a connection needs to remain idle before sending
keepalive probes and the time between individual keepalive
probes. It is currently effective on operating systems offering
the "TCP_KEEPIDLE" and "TCP_KEEPINTVL" socket options (meaning
Linux, *BSD/macOS, Windows, Solaris, and recent AIX, HP-UX and
more). Keepalive is used by the TCP stack to detect broken net-
works on idle connections. The number of missed keepalive
probes before declaring the connection down is OS dependent and
is commonly 8 (*BSD/macOS/AIX), 9 (Linux/AIX) or 5/10 (Windows),
and this number can be changed by specifying the curl option
"keepalive-cnt". Note that this option has no effect if
--no-keepalive is used.
If unspecified, the option defaults to 60 seconds.
If --keepalive-time is provided several times, the last set
value is used.
Example:
curl --keepalive-time 20 https://example.com
See also --no-keepalive, --keepalive-cnt and -m, --max-time.
--key <key>
(TLS SSH) Private key filename. Allows you to provide your pri-
vate key in this separate file. For SSH, if not specified, curl
tries the following candidates in order: "~/.ssh/id_rsa",
"~/.ssh/id_dsa", "./id_rsa", "./id_dsa".
If curl is built against OpenSSL library, and the engine pkcs11
or pkcs11 provider is available, then a PKCS#11 URI (RFC 7512)
can be used to specify a private key located in a PKCS#11 de-
vice. A string beginning with "pkcs11:" is interpreted as a
PKCS#11 URI. If a PKCS#11 URI is provided, then the --engine op-
tion is set as "pkcs11" if none was provided and the --key-type
option is set as "ENG" or "PROV" if none was provided (depending
on OpenSSL version).
If curl is built against Secure Transport or Schannel then this
option is ignored for TLS protocols (HTTPS, etc). Those backends
expect the private key to be already present in the keychain or
PKCS#12 file containing the certificate.
If --key is provided several times, the last set value is used.
Example:
curl --cert certificate --key here https://example.com
See also --key-type and -E, --cert.
--key-type <type>
(TLS) Private key file type. Specify which type your --key pro-
vided private key is. DER, PEM, and ENG are supported. If not
specified, PEM is assumed.
If --key-type is provided several times, the last set value is
used.
Example:
curl --key-type DER --key here https://example.com
See also --key.
--krb <level>
(FTP) Enable Kerberos authentication and use. The level must be
entered and should be one of 'clear', 'safe', 'confidential', or
'private'. Should you use a level that is not one of these,
'private' is used.
If --krb is provided several times, the last set value is used.
Example:
curl --krb clear ftp://example.com/
--krb requires that libcurl is built to support Kerberos. See
also --delegation and --ssl.
--libcurl <file>
Append this option to any ordinary curl command line, and you
get libcurl-using C source code written to the file that does
the equivalent of what your command-line operation does.
This option is global and does not need to be specified for each
use of --next.
If --libcurl is provided several times, the last set value is
used.
Example:
curl --libcurl client.c https://example.com
See also -v, --verbose.
--limit-rate <speed>
Specify the maximum transfer rate you want curl to use - for
both downloads and uploads. This feature is useful if you have a
limited pipe and you would like your transfer not to use your
entire bandwidth. To make it slower than it otherwise would be.
The given speed is measured in bytes/second, unless a suffix is
appended. Appending 'k' or 'K' counts the number as kilobytes,
'm' or 'M' makes it megabytes, while 'g' or 'G' makes it giga-
bytes. The suffixes (k, M, G, T, P) are 1024 based. For example
1k is 1024. Examples: 200K, 3m and 1G.
The rate limiting logic works on averaging the transfer speed to
no more than the set threshold over a period of multiple sec-
onds.
If you also use the -Y, --speed-limit option, that option takes
precedence and might cripple the rate-limiting slightly, to help
keep the speed-limit logic working.
If --limit-rate is provided several times, the last set value is
used.
Examples:
curl --limit-rate 100K https://example.com
curl --limit-rate 1000 https://example.com
curl --limit-rate 10M https://example.com
See also --rate, -Y, --speed-limit and -y, --speed-time.
-l, --list-only
(FTP POP3 SFTP FILE) When listing an FTP directory, force a
name-only view. Maybe particularly useful if the user wants to
machine-parse the contents of an FTP directory since the normal
directory view does not use a standard look or format. When used
like this, the option causes an NLST command to be sent to the
server instead of LIST.
Note: Some FTP servers list only files in their response to
NLST; they do not include sub-directories and symbolic links.
When listing an SFTP directory, this switch forces a name-only
view, one per line. This is especially useful if the user wants
to machine-parse the contents of an SFTP directory since the
normal directory view provides more information than just file-
names.
When retrieving a specific email from POP3, this switch forces a
LIST command to be performed instead of RETR. This is particu-
larly useful if the user wants to see if a specific message-id
exists on the server and what size it is.
For FILE, this option has no effect yet as directories are al-
ways listed in this mode.
Note: When combined with -X, --request, this option can be used
to send a UIDL command instead, so the user may use the email's
unique identifier rather than its message-id to make the re-
quest.
Providing --list-only multiple times has no extra effect. Dis-
able it again with --no-list-only.
Example:
curl --list-only ftp://example.com/dir/
See also -Q, --quote and -X, --request.
--local-port <range>
Set a preferred single number or range (FROM-TO) of local port
numbers to use for the connection(s). Note that port numbers by
nature are a scarce resource so setting this range to something
too narrow might cause unnecessary connection setup failures.
If --local-port is provided several times, the last set value is
used.
Example:
curl --local-port 1000-3000 https://example.com
See also -g, --globoff.
-L, --location
(HTTP) If the server reports that the requested page has moved
to a different location (indicated with a Location: header and a
3XX response code), this option makes curl redo the request to
the new place. If used together with -i, --show-headers or -I,
--head, headers from all requested pages are shown.
When authentication is used, or when sending a cookie with "-H
Cookie:", curl only sends its credentials to the initial host.
If a redirect takes curl to a different host, it does not get
the credentials passed on. See --location-trusted on how to
change this.
Limit the amount of redirects to follow by using the
--max-redirs option.
When curl follows a redirect and if the request is a POST, it
sends the following request with a GET if the HTTP response was
301, 302, or 303. If the response code was any other 3xx code,
curl resends the following request using the same unmodified
method.
You can tell curl to not change POST requests to GET after a 30x
response by using the dedicated options for that: --post301,
--post302 and --post303.
The method set with -X, --request overrides the method curl
would otherwise select to use.
Providing --location multiple times has no extra effect. Dis-
able it again with --no-location.
Example:
curl -L https://example.com
See also --resolve and --alt-svc.
--location-trusted
(HTTP) Instruct curl to follow HTTP redirects like -L, --loca-
tion, but permit curl to send credentials and other secrets
along to other hosts than the initial one.
This may or may not introduce a security breach if the site
redirects you to a site to which you send this sensitive data
to. Another host means that one or more of hostname, protocol
scheme or port number changed.
This option also allows curl to pass long cookies set explicitly
with -H, --header.
Providing --location-trusted multiple times has no extra effect.
Disable it again with --no-location-trusted.
Examples:
curl --location-trusted -u user:password https://example.com
curl --location-trusted -H "Cookie: session=abc" https://example.com
See also -u, --user.
--login-options <options>
(IMAP LDAP POP3 SMTP) Specify the login options to use during
server authentication.
You can use login options to specify protocol specific options
that may be used during authentication. At present only IMAP,
POP3 and SMTP support login options. For more information about
login options please see RFC 2384, RFC 5092 and the IETF draft
https://datatracker.ietf.org/doc/html/draft-earhart-url-smtp-00
Since 8.2.0, IMAP supports the login option "AUTH=+LOGIN". With
this option, curl uses the plain (not SASL) "LOGIN IMAP" command
even if the server advertises SASL authentication. Care should
be taken in using this option, as it sends your password over
the network in plain text. This does not work if the IMAP server
disables the plain "LOGIN" (e.g. to prevent password snooping).
If --login-options is provided several times, the last set value
is used.
Example:
curl --login-options 'AUTH=*' imap://example.com
See also -u, --user.
--mail-auth <address>
(SMTP) Specify a single address. This is used to specify the au-
thentication address (identity) of a submitted message that is
being relayed to another server.
If --mail-auth is provided several times, the last set value is
used.
Example:
curl --mail-auth user@example.com -T mail smtp://example.com/
See also --mail-rcpt and --mail-from.
--mail-from <address>
(SMTP) Specify a single address that the given mail should get
sent from.
If --mail-from is provided several times, the last set value is
used.
Example:
curl --mail-from user@example.com -T mail smtp://example.com/
See also --mail-rcpt and --mail-auth.
--mail-rcpt <address>
(SMTP) Specify a single email address, username or mailing list
name. Repeat this option several times to send to multiple re-
cipients.
When performing an address verification (VRFY command), the re-
cipient should be specified as the username or username and do-
main (as per Section 3.5 of RFC 5321).
When performing a mailing list expand (EXPN command), the recip-
ient should be specified using the mailing list name, such as
"Friends" or "London-Office".
--mail-rcpt can be used several times in a command line
Example:
curl --mail-rcpt user@example.net smtp://example.com
See also --mail-rcpt-allowfails.
--mail-rcpt-allowfails
(SMTP) When sending data to multiple recipients, by default curl
aborts SMTP conversation if at least one of the recipients
causes RCPT TO command to return an error.
The default behavior can be changed by passing --mail-rcpt-al-
lowfails command-line option which makes curl ignore errors and
proceed with the remaining valid recipients.
If all recipients trigger RCPT TO failures and this flag is
specified, curl still aborts the SMTP conversation and returns
the error received from to the last RCPT TO command.
Providing --mail-rcpt-allowfails multiple times has no extra ef-
fect. Disable it again with --no-mail-rcpt-allowfails.
Example:
curl --mail-rcpt-allowfails --mail-rcpt dest@example.com smtp://example.com
Added in 7.69.0. See also --mail-rcpt.
-M, --manual
Manual. Display the huge help text.
Example:
curl --manual
See also -v, --verbose, --libcurl and --trace.
--max-filesize <bytes>
(FTP HTTP MQTT) When set to a non-zero value, it specifies the
maximum size (in bytes) of a file to download. If the file re-
quested is larger than this value, the transfer does not start
and curl returns with exit code 63.
Setting the maximum value to zero disables the limit.
A size modifier may be used. For example, Appending 'k' or 'K'
counts the number as kilobytes, 'm' or 'M' makes it megabytes,
while 'g' or 'G' makes it gigabytes. Examples: 200K, 3m and 1G.
NOTE: before curl 8.4.0, when the file size is not known prior
to download, for such files this option has no effect even if
the file transfer ends up being larger than this given limit.
Starting with curl 8.4.0, this option aborts the transfer if it
reaches the threshold during transfer.
If --max-filesize is provided several times, the last set value
is used.
Example:
curl --max-filesize 100K https://example.com
See also --limit-rate.
--max-redirs <num>
(HTTP) Set the maximum number of redirections to follow. When
-L, --location is used, to prevent curl from following too many
redirects, by default, the limit is set to 50 redirects. Set
this option to -1 to make it unlimited.
If --max-redirs is provided several times, the last set value is
used.
Example:
curl --max-redirs 3 --location https://example.com
See also -L, --location.
-m, --max-time <seconds>
Set the maximum time in seconds that you allow each transfer to
take. Prevents your batch jobs from hanging for hours due to
slow networks or links going down. This option accepts decimal
values.
If you enable retrying the transfer (--retry) then the maximum
time counter is reset each time the transfer is retried. You can
use --retry-max-time to limit the retry time.
The decimal value needs to be provided using a dot (.) as deci-
mal separator - not the local version even if it might be using
another separator.
If --max-time is provided several times, the last set value is
used.
Examples:
curl --max-time 10 https://example.com
curl --max-time 2.92 https://example.com
See also --connect-timeout and --retry-max-time.
--metalink
This option was previously used to specify a Metalink resource.
Metalink support is disabled in curl for security reasons (added
in 7.78.0).
If --metalink is provided several times, the last set value is
used.
Example:
curl --metalink file https://example.com
See also -Z, --parallel.
--mptcp
Enable the use of Multipath TCP (MPTCP) for connections. MPTCP
is an extension to the standard TCP that allows multiple TCP
streams over different network paths between the same source and
destination. This can enhance bandwidth and improve reliability
by using multiple paths simultaneously.
MPTCP is beneficial in networks where multiple paths exist be-
tween clients and servers, such as mobile networks where a de-
vice may switch between WiFi and cellular data or in wired net-
works with multiple Internet Service Providers.
This option is currently only supported on Linux starting from
kernel 5.6. Only TCP connections are modified, hence this option
does not affect HTTP/3 (QUIC) or UDP connections.
The server curl connects to must also support MPTCP. If not, the
connection seamlessly falls back to TCP.
Providing --mptcp multiple times has no extra effect. Disable
it again with --no-mptcp.
Example:
curl --mptcp https://example.com
Added in 8.9.0. See also --tcp-fastopen.
--negotiate
(HTTP) Enable Negotiate (SPNEGO) authentication.
This option requires a library built with GSS-API or SSPI sup-
port. Use -V, --version to see if your curl supports
GSS-API/SSPI or SPNEGO.
When using this option, you must also provide a fake -u, --user
option to activate the authentication code properly. Sending a
'-u :' is enough as the username and password from the -u,
--user option are not actually used.
Providing --negotiate multiple times has no extra effect.
Example:
curl --negotiate -u : https://example.com
See also --basic, --ntlm, --anyauth and --proxy-negotiate.
-n, --netrc
Make curl scan the .netrc file in the user's home directory for
login name and password. This is typically used for FTP on Unix.
If used with HTTP, curl enables user authentication. See
netrc(5) and ftp(1) for details on the file format. curl does
not complain if that file does not have the right permissions
(it should be neither world- nor group-readable). The environ-
ment variable "HOME" is used to find the home directory.
On Windows two filenames in the home directory are checked:
.netrc and _netrc, preferring the former. Older versions on Win-
dows checked for _netrc only.
A quick and simple example of how to setup a .netrc to allow
curl to FTP to the machine host.example.com with username 'my-
self' and password 'secret' could look similar to:
machine host.example.com
login myself
password secret
Providing --netrc multiple times has no extra effect. Disable
it again with --no-netrc.
Example:
curl --netrc https://example.com
This option is mutually exclusive with --netrc-file and
--netrc-optional. See also --netrc-file, -K, --config and -u,
--user.
--netrc-file <filename>
Set the netrc file to use. Similar to -n, --netrc, except that
you also provide the path (absolute or relative).
It abides by --netrc-optional if specified.
If --netrc-file is provided several times, the last set value is
used.
Example:
curl --netrc-file netrc https://example.com
This option is mutually exclusive with -n, --netrc. See also
-n, --netrc, -u, --user and -K, --config.
--netrc-optional
Similar to -n, --netrc, but this option makes the .netrc usage
optional and not mandatory as the -n, --netrc option does.
Providing --netrc-optional multiple times has no extra effect.
Disable it again with --no-netrc-optional.
Example:
curl --netrc-optional https://example.com
This option is mutually exclusive with -n, --netrc. See also
--netrc-file.
-:, --next
Use a separate operation for the following URL and associated
options. This allows you to send several URL requests, each with
their own specific options, for example, such as different user-
names or custom requests for each.
-:, --next resets all local options and only global ones have
their values survive over to the operation following the -:,
--next instruction. Global options include -v, --verbose,
--trace, --trace-ascii and --fail-early.
For example, you can do both a GET and a POST in a single com-
mand line:
curl www1.example.com --next -d postthis www2.example.com
--next can be used several times in a command line
Examples:
curl https://example.com --next -d postthis www2.example.com
curl -I https://example.com --next https://example.net/
See also -Z, --parallel and -K, --config.
--no-alpn
(HTTPS) Disable the ALPN TLS extension. ALPN is enabled by de-
fault if libcurl was built with an SSL library that supports
ALPN. ALPN is used by a libcurl that supports HTTP/2 to negoti-
ate HTTP/2 support with the server during https sessions.
Note that this is the negated option name documented. You can
use --alpn to enable ALPN.
Providing --no-alpn multiple times has no extra effect. Disable
it again with --alpn.
Example:
curl --no-alpn https://example.com
--no-alpn requires that libcurl is built to support TLS. See
also --no-npn and --http2.
-N, --no-buffer
Disable the buffering of the output stream. In normal work situ-
ations, curl uses a standard buffered output stream that has the
effect that it outputs the data in chunks, not necessarily ex-
actly when the data arrives. Using this option disables that
buffering.
Note that this is the negated option name documented. You can
use --buffer to enable buffering again.
Providing --no-buffer multiple times has no extra effect. Dis-
able it again with --buffer.
Example:
curl --no-buffer https://example.com
See also -#, --progress-bar.
--no-clobber
When used in conjunction with the -o, --output, -J, --re-
mote-header-name, -O, --remote-name, or --remote-name-all op-
tions, curl avoids overwriting files that already exist. In-
stead, a dot and a number gets appended to the name of the file
that would be created, up to filename.100 after which it does
not create any file.
Note that this is the negated option name documented. You can
thus use --clobber to enforce the clobbering, even if -J, --re-
mote-header-name is specified.
The -C, --continue-at option cannot be used together with
--no-clobber.
Providing --no-clobber multiple times has no extra effect. Dis-
able it again with --clobber.
Example:
curl --no-clobber --output local/dir/file https://example.com
Added in 7.83.0. See also -o, --output and -O, --remote-name.
--no-keepalive
Disable the use of keepalive messages on the TCP connection.
curl otherwise enables them by default.
Note that this is the negated option name documented. You can
thus use --keepalive to enforce keepalive.
Providing --no-keepalive multiple times has no extra effect.
Disable it again with --keepalive.
Example:
curl --no-keepalive https://example.com
See also --keepalive-time and --keepalive-cnt.
--no-npn
(HTTPS) curl never uses NPN, this option has no effect (added in
7.86.0).
Disable the NPN TLS extension. NPN is enabled by default if
libcurl was built with an SSL library that supports NPN. NPN is
used by a libcurl that supports HTTP/2 to negotiate HTTP/2 sup-
port with the server during https sessions.
Providing --no-npn multiple times has no extra effect. Disable
it again with --npn.
Example:
curl --no-npn https://example.com
--no-npn requires that libcurl is built to support TLS. See
also --no-alpn and --http2.
--no-progress-meter
Option to switch off the progress meter output without muting or
otherwise affecting warning and informational messages like -s,
--silent does.
Note that this is the negated option name documented. You can
thus use --progress-meter to enable the progress meter again.
Providing --no-progress-meter multiple times has no extra ef-
fect. Disable it again with --progress-meter.
Example:
curl --no-progress-meter -o store https://example.com
Added in 7.67.0. See also -v, --verbose and -s, --silent.
--no-sessionid
(TLS) Disable curl's use of SSL session-ID caching. By default
all transfers are done using the cache. Note that while nothing
should ever get hurt by attempting to reuse SSL session-IDs,
there seem to be broken SSL implementations in the wild that may
require you to disable this in order for you to succeed.
Note that this is the negated option name documented. You can
thus use --sessionid to enforce session-ID caching.
Providing --no-sessionid multiple times has no extra effect.
Disable it again with --sessionid.
Example:
curl --no-sessionid https://example.com
See also -k, --insecure.
--noproxy <no-proxy-list>
Comma-separated list of hosts for which not to use a proxy, if
one is specified. The only wildcard is a single "*" character,
which matches all hosts, and effectively disables the proxy.
Each name in this list is matched as either a domain which con-
tains the hostname, or the hostname itself. For example, "lo-
cal.com" would match "local.com", "local.com:80", and "www.lo-
cal.com", but not "www.notlocal.com".
This option overrides the environment variables that disable the
proxy ("no_proxy" and "NO_PROXY"). If there is an environment
variable disabling a proxy, you can set the no proxy list to ""
to override it.
IP addresses specified to this option can be provided using CIDR
notation (added in 7.86.0): an appended slash and number speci-
fies the number of network bits out of the address to use in the
comparison. For example "192.168.0.0/16" would match all ad-
dresses starting with "192.168".
If --noproxy is provided several times, the last set value is
used.
Example:
curl --noproxy "www.example" https://example.com
See also -x, --proxy.
--ntlm (HTTP) Use NTLM authentication. The NTLM authentication method
was designed by Microsoft and is used by IIS web servers. It is
a proprietary protocol, reverse-engineered by clever people and
implemented in curl based on their efforts. This kind of behav-
ior should not be endorsed, you should encourage everyone who
uses NTLM to switch to a public and documented authentication
method instead, such as Digest.
If you want to enable NTLM for your proxy authentication, then
use --proxy-ntlm.
Providing --ntlm multiple times has no extra effect.
Example:
curl --ntlm -u user:password https://example.com
--ntlm requires that libcurl is built to support TLS. This op-
tion is mutually exclusive with --basic, --negotiate, --digest
and --anyauth. See also --proxy-ntlm.
--ntlm-wb
(HTTP) Deprecated option (added in 8.8.0).
Enabled NTLM much in the style --ntlm does, but handed over the
authentication to a separate executable that was executed when
needed.
Providing --ntlm-wb multiple times has no extra effect.
Example:
curl --ntlm-wb -u user:password https://example.com
See also --ntlm and --proxy-ntlm.
--oauth2-bearer <token>
(IMAP LDAP POP3 SMTP HTTP) Specify the Bearer Token for OAUTH
2.0 server authentication. The Bearer Token is used in conjunc-
tion with the username which can be specified as part of the
--url or -u, --user options.
The Bearer Token and username are formatted according to RFC
6750.
If --oauth2-bearer is provided several times, the last set value
is used.
Example:
curl --oauth2-bearer "mF_9.B5f-4.1JqM" https://example.com
See also --basic, --ntlm and --digest.
-o, --output <file>
Write output to the given file instead of stdout. If you are us-
ing globbing to fetch multiple documents, you should quote the
URL and you can use "#" followed by a number in the filename.
That variable is then replaced with the current string for the
URL being fetched. Like in:
curl "http://{one,two}.example.com" -o "file_#1.txt"
or use several variables like:
curl "http://{site,host}.host[1-5].example" -o "#1_#2"
You may use this option as many times as the number of URLs you
have. For example, if you specify two URLs on the same command
line, you can use it like this:
curl -o aa example.com -o bb example.net
and the order of the -o options and the URLs does not matter,
just that the first -o is for the first URL and so on, so the
above command line can also be written as
curl example.com example.net -o aa -o bb
See also the --create-dirs option to create the local directo-
ries dynamically. Specifying the output as '-' (a single dash)
passes the output to stdout.
To suppress response bodies, you can redirect output to
/dev/null:
curl example.com -o /dev/null
Or for Windows:
curl example.com -o nul
Specify the filename as single minus to force the output to std-
out, to override curl's internal binary output in terminal pre-
vention:
curl https://example.com/jpeg -o -
--output is associated with a single URL. Use it once per URL
when you use several URLs in a command line.
Examples:
curl -o file https://example.com
curl "http://{one,two}.example.com" -o "file_#1.txt"
curl "http://{site,host}.host[1-5].example" -o "#1_#2"
curl -o file https://example.com -o file2 https://example.net
See also -O, --remote-name, --remote-name-all and -J, --re-
mote-header-name.
--output-dir <dir>
Specify the directory in which files should be stored, when -O,
--remote-name or -o, --output are used.
The given output directory is used for all URLs and output op-
tions on the command line, up until the first -:, --next.
If the specified target directory does not exist, the operation
fails unless --create-dirs is also used.
If --output-dir is provided several times, the last set value is
used.
Example:
curl --output-dir "tmp" -O https://example.com
Added in 7.73.0. See also -O, --remote-name and -J, --re-
mote-header-name.
-Z, --parallel
Make curl perform all transfers in parallel as compared to the
regular serial manner. Parallel transfer means that curl runs up
to N concurrent transfers simultaneously and if there are more
than N transfers to handle, it starts new ones when earlier
transfers finish.
With parallel transfers, the progress meter output is different
from when doing serial transfers, as it then displays the trans-
fer status for multiple transfers in a single line.
The maximum amount of concurrent transfers is set with --paral-
lel-max and it defaults to 50.
This option is global and does not need to be specified for each
use of --next.
Providing --parallel multiple times has no extra effect. Dis-
able it again with --no-parallel.
Example:
curl --parallel https://example.com -o file1 https://example.com -o file2
Added in 7.66.0. See also -:, --next, -v, --verbose, --paral-
lel-max and --parallel-immediate.
--parallel-immediate
When doing parallel transfers, this option instructs curl to
prefer opening up more connections in parallel at once rather
than waiting to see if new transfers can be added as multiplexed
streams on another connection.
By default, without this option set, curl prefers to wait a lit-
tle and multiplex new transfers over existing connections. It
keeps the number of connections low at the expense of risking a
slightly slower transfer startup.
This option is global and does not need to be specified for each
use of --next.
Providing --parallel-immediate multiple times has no extra ef-
fect. Disable it again with --no-parallel-immediate.
Example:
curl --parallel-immediate -Z https://example.com -o file1 https://example.com -o file2
Added in 7.68.0. See also -Z, --parallel and --parallel-max.
--parallel-max <num>
When asked to do parallel transfers, using -Z, --parallel, this
option controls the maximum amount of transfers to do simultane-
ously.
The default is 50. 300 is the largest supported value.
This option is global and does not need to be specified for each
use of --next.
If --parallel-max is provided several times, the last set value
is used.
Example:
curl --parallel-max 100 -Z https://example.com ftp://example.com/
Added in 7.66.0. See also -Z, --parallel.
--pass <phrase>
(SSH TLS) Passphrase for the private key used for SSH or TLS.
If --pass is provided several times, the last set value is used.
Example:
curl --pass secret --key file https://example.com
See also --key and -u, --user.
--path-as-is
Do not handle sequences of /../ or /./ in the given URL path.
Normally curl squashes or merges them according to standards but
with this option set you tell it not to do that.
Providing --path-as-is multiple times has no extra effect. Dis-
able it again with --no-path-as-is.
Example:
curl --path-as-is https://example.com/../../etc/passwd
See also --request-target.
--pinnedpubkey <hashes>
(TLS) Use the specified public key file (or hashes) to verify
the peer. This can be a path to a file which contains a single
public key in PEM or DER format, or any number of base64 encoded
sha256 hashes preceded by 'sha256//' and separated by ';'.
When negotiating a TLS or SSL connection, the server sends a
certificate indicating its identity. A public key is extracted
from this certificate and if it does not exactly match the pub-
lic key provided to this option, curl aborts the connection be-
fore sending or receiving any data.
This option is independent of option -k, --insecure. If you use
both options together then the peer is still verified by public
key.
PEM/DER support:
OpenSSL and GnuTLS, wolfSSL, mbedTLS, Secure Transport macOS
10.7+/iOS 10+, Schannel
sha256 support:
OpenSSL, GnuTLS and wolfSSL, mbedTLS, Secure Transport macOS
10.7+/iOS 10+, Schannel
Other SSL backends not supported.
If --pinnedpubkey is provided several times, the last set value
is used.
Examples:
curl --pinnedpubkey keyfile https://example.com
curl --pinnedpubkey 'sha256//ce118b51897f4452dc' https://example.com
See also --hostpubsha256.
--post301
(HTTP) Respect RFC 7231/6.4.2 and do not convert POST requests
into GET requests when following a 301 redirect. The non-RFC be-
havior is ubiquitous in web browsers, so curl does the conver-
sion by default to maintain consistency. However, a server may
require a POST to remain a POST after such a redirection. This
option is meaningful only when using -L, --location.
Providing --post301 multiple times has no extra effect. Disable
it again with --no-post301.
Example:
curl --post301 --location -d "data" https://example.com
See also --post302, --post303 and -L, --location.
--post302
(HTTP) Respect RFC 7231/6.4.3 and do not convert POST requests
into GET requests when following a 302 redirect. The non-RFC be-
havior is ubiquitous in web browsers, so curl does the conver-
sion by default to maintain consistency. However, a server may
require a POST to remain a POST after such a redirection. This
option is meaningful only when using -L, --location.
Providing --post302 multiple times has no extra effect. Disable
it again with --no-post302.
Example:
curl --post302 --location -d "data" https://example.com
See also --post301, --post303 and -L, --location.
--post303
(HTTP) Violate RFC 7231/6.4.4 and do not convert POST requests
into GET requests when following 303 redirect. A server may re-
quire a POST to remain a POST after a 303 redirection. This op-
tion is meaningful only when using -L, --location.
Providing --post303 multiple times has no extra effect. Disable
it again with --no-post303.
Example:
curl --post303 --location -d "data" https://example.com
See also --post302, --post301 and -L, --location.
--preproxy <[protocol://]host[:port]>
Use the specified SOCKS proxy before connecting to an HTTP or
HTTPS -x, --proxy. In such a case curl first connects to the
SOCKS proxy and then connects (through SOCKS) to the HTTP or
HTTPS proxy. Hence pre proxy.
The pre proxy string should be specified with a protocol:// pre-
fix to specify alternative proxy protocols. Use socks4://,
socks4a://, socks5:// or socks5h:// to request the specific
SOCKS version to be used. No protocol specified makes curl de-
fault to SOCKS4.
If the port number is not specified in the proxy string, it is
assumed to be 1080.
User and password that might be provided in the proxy string are
URL decoded by curl. This allows you to pass in special charac-
ters such as @ by using %40 or pass in a colon with %3a.
If --preproxy is provided several times, the last set value is
used.
Example:
curl --preproxy socks5://proxy.example -x http://http.example https://example.com
See also -x, --proxy and --socks5.
-#, --progress-bar
Make curl display transfer progress as a simple progress bar in-
stead of the standard, more informational, meter.
This progress bar draws a single line of '#' characters across
the screen and shows a percentage if the transfer size is known.
For transfers without a known size, there is a space ship
(-=o=-) that moves back and forth but only while data is being
transferred, with a set of flying hash sign symbols on top.
This option is global and does not need to be specified for each
use of --next.
Providing --progress-bar multiple times has no extra effect.
Disable it again with --no-progress-bar.
Example:
curl -# -O https://example.com
See also --styled-output.
--proto <protocols>
Limit what protocols to allow for transfers. Protocols are eval-
uated left to right, are comma separated, and are each a proto-
col name or 'all', optionally prefixed by zero or more modi-
fiers. Available modifiers are:
+ Permit this protocol in addition to protocols already
permitted (this is the default if no modifier is used).
- Deny this protocol, removing it from the list of proto-
cols already permitted.
= Permit only this protocol (ignoring the list already per-
mitted), though subject to later modification by subse-
quent entries in the comma separated list.
For example: --proto -ftps uses the default protocols, but dis-
ables ftps
--proto -all,https,+http only enables http and https
--proto =http,https also only enables http and https
Unknown and disabled protocols produce a warning. This allows
scripts to safely rely on being able to disable potentially dan-
gerous protocols, without relying upon support for that protocol
being built into curl to avoid an error.
This option can be used multiple times, in which case the effect
is the same as concatenating the protocols into one instance of
the option.
If --proto is provided several times, the last set value is
used.
Example:
curl --proto =http,https,sftp https://example.com
See also --proto-redir and --proto-default.
--proto-default <protocol>
Use protocol for any provided URL missing a scheme.
An unknown or unsupported protocol causes error CURLE_UNSUP-
PORTED_PROTOCOL.
This option does not change the default proxy protocol (http).
Without this option set, curl guesses protocol based on the
hostname, see --url for details.
If --proto-default is provided several times, the last set value
is used.
Example:
curl --proto-default https ftp.example.com
See also --proto and --proto-redir.
--proto-redir <protocols>
Limit what protocols to allow on redirects. Protocols denied by
--proto are not overridden by this option. See --proto for how
protocols are represented.
Example, allow only HTTP and HTTPS on redirect:
curl --proto-redir -all,http,https http://example.com
By default curl only allows HTTP, HTTPS, FTP and FTPS on redi-
rects (added in 7.65.2). Specifying all or +all enables all pro-
tocols on redirects, which is not good for security.
If --proto-redir is provided several times, the last set value
is used.
Example:
curl --proto-redir =http,https https://example.com
See also --proto.
-x, --proxy <[protocol://]host[:port]>
Use the specified proxy.
The proxy string can be specified with a protocol:// prefix. No
protocol specified or http:// it is treated as an HTTP proxy.
Use socks4://, socks4a://, socks5:// or socks5h:// to request a
specific SOCKS version to be used.
Unix domain sockets are supported for socks proxy. Set localhost
for the host part. e.g. socks5h://localhost/path/to/socket.sock
HTTPS proxy support works with the https:// protocol prefix for
OpenSSL and GnuTLS. It also works for BearSSL, mbedTLS, Rustls,
Schannel, Secure Transport and wolfSSL (added in 7.87.0).
Unrecognized and unsupported proxy protocols cause an error.
Ancient curl versions ignored unknown schemes and used http://
instead.
If the port number is not specified in the proxy string, it is
assumed to be 1080.
This option overrides existing environment variables that set
the proxy to use. If there is an environment variable setting a
proxy, you can set proxy to "" to override it.
All operations that are performed over an HTTP proxy are trans-
parently converted to HTTP. It means that certain protocol spe-
cific operations might not be available. This is not the case if
you can tunnel through the proxy, as one with the -p, --proxy-
tunnel option.
User and password that might be provided in the proxy string are
URL decoded by curl. This allows you to pass in special charac-
ters such as @ by using %40 or pass in a colon with %3a.
The proxy host can be specified the same way as the proxy envi-
ronment variables, including the protocol prefix (http://) and
the embedded user + password.
When a proxy is used, the active FTP mode as set with -P,
--ftp-port, cannot be used.
Doing FTP over an HTTP proxy without -p, --proxytunnel makes
curl do HTTP with an FTP URL over the proxy. For such transfers,
common FTP specific options do not work, including --ssl-reqd
and --ftp-ssl-control.
If --proxy is provided several times, the last set value is
used.
Example:
curl --proxy http://proxy.example https://example.com
See also --socks5 and --proxy-basic.
--proxy-anyauth
Automatically pick a suitable authentication method when commu-
nicating with the given HTTP proxy. This might cause an extra
request/response round-trip.
Providing --proxy-anyauth multiple times has no extra effect.
Example:
curl --proxy-anyauth --proxy-user user:passwd -x proxy https://example.com
See also -x, --proxy, --proxy-basic and --proxy-digest.
--proxy-basic
Use HTTP Basic authentication when communicating with the given
proxy. Use --basic for enabling HTTP Basic with a remote host.
Basic is the default authentication method curl uses with prox-
ies.
Providing --proxy-basic multiple times has no extra effect.
Example:
curl --proxy-basic --proxy-user user:passwd -x proxy https://example.com
See also -x, --proxy, --proxy-anyauth and --proxy-digest.
--proxy-ca-native
(TLS) Use the operating system's native CA store for certificate
verification of the HTTPS proxy.
This option is independent of other HTTPS proxy CA certificate
locations set at run time or build time. Those locations are
searched in addition to the native CA store.
Equivalent to --ca-native but used in HTTPS proxy context. Refer
to --ca-native for TLS backend limitations.
Providing --proxy-ca-native multiple times has no extra effect.
Disable it again with --no-proxy-ca-native.
Example:
curl --proxy-ca-native https://example.com
Added in 8.2.0. See also --ca-native, --cacert, --capath,
--dump-ca-embed and -k, --insecure.
--proxy-cacert <file>
Use the specified certificate file to verify the HTTPS proxy.
The file may contain multiple CA certificates. The certifi-
cate(s) must be in PEM format.
This allows you to use a different trust for the proxy compared
to the remote server connected to via the proxy.
Equivalent to --cacert but used in HTTPS proxy context.
If --proxy-cacert is provided several times, the last set value
is used.
Example:
curl --proxy-cacert CA-file.txt -x https://proxy https://example.com
See also --proxy-capath, --cacert, --capath, --dump-ca-embed and
-x, --proxy.
--proxy-capath <dir>
Same as --capath but used in HTTPS proxy context.
Use the specified certificate directory to verify the proxy.
Multiple paths can be provided by separating them with colon
(":") (e.g. "path1:path2:path3"). The certificates must be in
PEM format, and if curl is built against OpenSSL, the directory
must have been processed using the c_rehash utility supplied
with OpenSSL. Using --proxy-capath can allow OpenSSL-powered
curl to make SSL-connections much more efficiently than using
--proxy-cacert if the --proxy-cacert file contains many CA cer-
tificates.
If this option is set, the default capath value is ignored.
If --proxy-capath is provided several times, the last set value
is used.
Example:
curl --proxy-capath /local/directory -x https://proxy https://example.com
See also --proxy-cacert, -x, --proxy, --capath and --dump-ca-em-
bed.
--proxy-cert <cert[:passwd]>
Use the specified client certificate file when communicating
with an HTTPS proxy. The certificate must be in PKCS#12 format
if using Secure Transport, or PEM format if using any other en-
gine. If the optional password is not specified, it is queried
for on the terminal. Use --proxy-key to provide the private key.
This option is the equivalent to -E, --cert but used in HTTPS
proxy context.
If --proxy-cert is provided several times, the last set value is
used.
Example:
curl --proxy-cert file -x https://proxy https://example.com
See also -x, --proxy, --proxy-key and --proxy-cert-type.
--proxy-cert-type <type>
Set type of the provided client certificate when using HTTPS
proxy. PEM, DER, ENG, PROV and P12 are recognized types.
The default type depends on the TLS backend and is usually PEM,
however for Secure Transport and Schannel it is P12. If
--proxy-cert is a pkcs11: URI then ENG or PROV is the default
type (depending on OpenSSL version).
Equivalent to --cert-type but used in HTTPS proxy context.
If --proxy-cert-type is provided several times, the last set
value is used.
Example:
curl --proxy-cert-type PEM --proxy-cert file -x https://proxy https://example.com
See also --proxy-cert and --proxy-key.
--proxy-ciphers <list>
(TLS) Same as --ciphers but used in HTTPS proxy context.
Specify which cipher suites to use in the connection to your
HTTPS proxy when it negotiates TLS 1.2 (1.1, 1.0). The list of
ciphers suites must specify valid ciphers. Read up on cipher
suite details on this URL:
https://curl.se/docs/ssl-ciphers.html
If --proxy-ciphers is provided several times, the last set value
is used.
Example:
curl --proxy-ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256 -x https://proxy https://example.com
See also --proxy-tls13-ciphers, --ciphers and -x, --proxy.
--proxy-crlfile <file>
Provide filename for a PEM formatted file with a Certificate Re-
vocation List that specifies peer certificates that are consid-
ered revoked when communicating with an HTTPS proxy.
Equivalent to --crlfile but only used in HTTPS proxy context.
If --proxy-crlfile is provided several times, the last set value
is used.
Example:
curl --proxy-crlfile rejects.txt -x https://proxy https://example.com
See also --crlfile and -x, --proxy.
--proxy-digest
Use HTTP Digest authentication when communicating with the given
proxy. Use --digest for enabling HTTP Digest with a remote host.
Providing --proxy-digest multiple times has no extra effect.
Example:
curl --proxy-digest --proxy-user user:passwd -x proxy https://example.com
See also -x, --proxy, --proxy-anyauth and --proxy-basic.
--proxy-header <header/@file>
(HTTP) Extra header to include in the request when sending HTTP
to a proxy. You may specify any number of extra headers. This is
the equivalent option to -H, --header but is for proxy communi-
cation only like in CONNECT requests when you want a separate
header sent to the proxy to what is sent to the actual remote
host.
curl makes sure that each header you add/replace is sent with
the proper end-of-line marker, you should thus not add that as a
part of the header content: do not add newlines or carriage re-
turns, they only mess things up for you.
Headers specified with this option are not included in requests
that curl knows are not to be sent to a proxy.
This option can take an argument in @filename style, which then
adds a header for each line in the input file. Using @- makes
curl read the headers from stdin.
This option can be used multiple times to add/replace/remove
multiple headers.
--proxy-header can be used several times in a command line
Examples:
curl --proxy-header "X-First-Name: Joe" -x http://proxy https://example.com
curl --proxy-header "User-Agent: surprise" -x http://proxy https://example.com
curl --proxy-header "Host:" -x http://proxy https://example.com
See also -x, --proxy.
--proxy-http2
(HTTP) Negotiate HTTP/2 with an HTTPS proxy. The proxy might
still only offer HTTP/1 and then curl sticks to using that ver-
sion.
This has no effect for any other kinds of proxies.
Providing --proxy-http2 multiple times has no extra effect.
Disable it again with --no-proxy-http2.
Example:
curl --proxy-http2 -x proxy https://example.com
--proxy-http2 requires that libcurl is built to support HTTP/2.
Added in 8.1.0. See also -x, --proxy.
--proxy-insecure
Same as -k, --insecure but used in HTTPS proxy context.
Every secure connection curl makes is verified to be secure be-
fore the transfer takes place. This option makes curl skip the
verification step with a proxy and proceed without checking.
When this option is not used for a proxy using HTTPS, curl veri-
fies the proxy's TLS certificate before it continues: that the
certificate contains the right name which matches the hostname
and that the certificate has been signed by a CA certificate
present in the cert store. See this online resource for further
details: https://curl.se/docs/sslcerts.html
WARNING: using this option makes the transfer to the proxy inse-
cure.
Providing --proxy-insecure multiple times has no extra effect.
Disable it again with --no-proxy-insecure.
Example:
curl --proxy-insecure -x https://proxy https://example.com
See also -x, --proxy and -k, --insecure.
--proxy-key <key>
Specify the filename for your private key when using client cer-
tificates with your HTTPS proxy. This option is the equivalent
to --key but used in HTTPS proxy context.
If --proxy-key is provided several times, the last set value is
used.
Example:
curl --proxy-key here -x https://proxy https://example.com
See also --proxy-key-type and -x, --proxy.
--proxy-key-type <type>
Specify the private key file type your --proxy-key provided pri-
vate key uses. DER, PEM, and ENG are supported. If not speci-
fied, PEM is assumed.
Equivalent to --key-type but used in HTTPS proxy context.
If --proxy-key-type is provided several times, the last set
value is used.
Example:
curl --proxy-key-type DER --proxy-key here -x https://proxy https://example.com
See also --proxy-key and -x, --proxy.
--proxy-negotiate
Use HTTP Negotiate (SPNEGO) authentication when communicating
with the given proxy. Use --negotiate for enabling HTTP Negoti-
ate (SPNEGO) with a remote host.
Providing --proxy-negotiate multiple times has no extra effect.
Example:
curl --proxy-negotiate --proxy-user user:passwd -x proxy https://example.com
See also --proxy-anyauth, --proxy-basic and --proxy-ser-
vice-name.
--proxy-ntlm
Use HTTP NTLM authentication when communicating with the given
proxy. Use --ntlm for enabling NTLM with a remote host.
Providing --proxy-ntlm multiple times has no extra effect.
Example:
curl --proxy-ntlm --proxy-user user:passwd -x http://proxy https://example.com
See also --proxy-negotiate, --proxy-anyauth and -U,
--proxy-user.
--proxy-pass <phrase>
Passphrase for the private key for HTTPS proxy client certifi-
cate.
Equivalent to --pass but used in HTTPS proxy context.
If --proxy-pass is provided several times, the last set value is
used.
Example:
curl --proxy-pass secret --proxy-key here -x https://proxy https://example.com
See also -x, --proxy and --proxy-key.
--proxy-pinnedpubkey <hashes>
(TLS) Use the specified public key file (or hashes) to verify
the proxy. This can be a path to a file which contains a single
public key in PEM or DER format, or any number of base64 encoded
sha256 hashes preceded by 'sha256//' and separated by ';'.
When negotiating a TLS or SSL connection, the server sends a
certificate indicating its identity. A public key is extracted
from this certificate and if it does not exactly match the pub-
lic key provided to this option, curl aborts the connection be-
fore sending or receiving any data.
Before curl 8.10.0 this option did not work due to a bug.
If --proxy-pinnedpubkey is provided several times, the last set
value is used.
Examples:
curl --proxy-pinnedpubkey keyfile https://example.com
curl --proxy-pinnedpubkey 'sha256//ce118b51897f4452dc' https://example.com
See also --pinnedpubkey and -x, --proxy.
--proxy-service-name <name>
Set the service name for SPNEGO when doing proxy authentication.
If --proxy-service-name is provided several times, the last set
value is used.
Example:
curl --proxy-service-name "shrubbery" -x proxy https://example.com
See also --service-name, -x, --proxy and --proxy-negotiate.
--proxy-ssl-allow-beast
Do not work around a security flaw in the TLS1.0 protocol known
as BEAST when communicating to an HTTPS proxy. If this option is
not used, the TLS layer may use workarounds known to cause in-
teroperability problems with some older server implementations.
This option only changes how curl does TLS 1.0 with an HTTPS
proxy and has no effect on later TLS versions.
WARNING: this option loosens the TLS security, and by using this
flag you ask for exactly that.
Equivalent to --ssl-allow-beast but used in HTTPS proxy context.
Providing --proxy-ssl-allow-beast multiple times has no extra
effect. Disable it again with --no-proxy-ssl-allow-beast.
Example:
curl --proxy-ssl-allow-beast -x https://proxy https://example.com
See also --ssl-allow-beast and -x, --proxy.
--proxy-ssl-auto-client-cert
Same as --ssl-auto-client-cert but used in HTTPS proxy context.
This is only supported by Schannel.
Providing --proxy-ssl-auto-client-cert multiple times has no ex-
tra effect. Disable it again with --no-proxy-ssl-auto-client-
cert.
Example:
curl --proxy-ssl-auto-client-cert -x https://proxy https://example.com
Added in 7.77.0. See also --ssl-auto-client-cert and -x,
--proxy.
--proxy-tls13-ciphers <list>
(TLS) Same as --tls13-ciphers but used in HTTPS proxy context.
Specify which cipher suites to use in the connection to your
HTTPS proxy when it negotiates TLS 1.3. The list of ciphers
suites must specify valid ciphers. Read up on TLS 1.3 cipher
suite details on this URL:
https://curl.se/docs/ssl-ciphers.html
This option is used when curl is built to use OpenSSL 1.1.1 or
later, Schannel, wolfSSL, or mbedTLS 3.6.0 or later.
Before curl 8.10.0 with mbedTLS or wolfSSL, TLS 1.3 cipher
suites were set by using the --proxy-ciphers option.
If --proxy-tls13-ciphers is provided several times, the last set
value is used.
Example:
curl --proxy-tls13-ciphers TLS_AES_128_GCM_SHA256 -x proxy https://example.com
Added in 7.61.0. See also --proxy-ciphers, --tls13-ciphers and
-x, --proxy.
--proxy-tlsauthtype <type>
Set TLS authentication type with HTTPS proxy. The only supported
option is "SRP", for TLS-SRP (RFC 5054). This option works only
if the underlying libcurl is built with TLS-SRP support.
Equivalent to --tlsauthtype but used in HTTPS proxy context.
If --proxy-tlsauthtype is provided several times, the last set
value is used.
Example:
curl --proxy-tlsauthtype SRP -x https://proxy https://example.com
See also -x, --proxy, --proxy-tlsuser and --proxy-tlspassword.
--proxy-tlspassword <string>
Set password to use with the TLS authentication method specified
with --proxy-tlsauthtype when using HTTPS proxy. Requires that
--proxy-tlsuser is set.
This option does not work with TLS 1.3.
Equivalent to --tlspassword but used in HTTPS proxy context.
If --proxy-tlspassword is provided several times, the last set
value is used.
Example:
curl --proxy-tlspassword passwd -x https://proxy https://example.com
See also -x, --proxy and --proxy-tlsuser.
--proxy-tlsuser <name>
Set username for use for HTTPS proxy with the TLS authentication
method specified with --proxy-tlsauthtype. Requires that
--proxy-tlspassword also is set.
This option does not work with TLS 1.3.
If --proxy-tlsuser is provided several times, the last set value
is used.
Example:
curl --proxy-tlsuser smith -x https://proxy https://example.com
See also -x, --proxy and --proxy-tlspassword.
--proxy-tlsv1
Use at least TLS version 1.x when negotiating with an HTTPS
proxy. That means TLS version 1.0 or higher
Equivalent to -1, --tlsv1 but for an HTTPS proxy context.
Providing --proxy-tlsv1 multiple times has no extra effect.
Example:
curl --proxy-tlsv1 -x https://proxy https://example.com
See also -x, --proxy.
-U, --proxy-user <user:password>
Specify the username and password to use for proxy authentica-
tion.
If you use a Windows SSPI-enabled curl binary and do either Ne-
gotiate or NTLM authentication then you can tell curl to select
the username and password from your environment by specifying a
single colon with this option: "-U :".
On systems where it works, curl hides the given option argument
from process listings. This is not enough to protect credentials
from possibly getting seen by other users on the same system as
they still are visible for a moment before being cleared. Such
sensitive data should be retrieved from a file instead or simi-
lar and never used in clear text in a command line.
If --proxy-user is provided several times, the last set value is
used.
Example:
curl --proxy-user smith:secret -x proxy https://example.com
See also --proxy-pass.
--proxy1.0 <host[:port]>
Use the specified HTTP 1.0 proxy. If the port number is not
specified, it is assumed at port 1080.
The only difference between this and the HTTP proxy option -x,
--proxy, is that attempts to use CONNECT through the proxy spec-
ifies an HTTP 1.0 protocol instead of the default HTTP 1.1.
Providing --proxy1.0 multiple times has no extra effect.
Example:
curl --proxy1.0 http://proxy https://example.com
See also -x, --proxy, --socks5 and --preproxy.
-p, --proxytunnel
When an HTTP proxy is used -x, --proxy, this option makes curl
tunnel the traffic through the proxy. The tunnel approach is
made with the HTTP proxy CONNECT request and requires that the
proxy allows direct connection to the remote port number curl
wants to tunnel through to.
To suppress proxy CONNECT response headers when curl is set to
output headers use --suppress-connect-headers.
Providing --proxytunnel multiple times has no extra effect.
Disable it again with --no-proxytunnel.
Example:
curl --proxytunnel -x http://proxy https://example.com
See also -x, --proxy.
--pubkey <key>
(SFTP SCP) Public key filename. Allows you to provide your pub-
lic key in this separate file.
curl attempts to automatically extract the public key from the
private key file, so passing this option is generally not re-
quired. Note that this public key extraction requires libcurl to
be linked against a copy of libssh2 1.2.8 or higher that is it-
self linked against OpenSSL.
If --pubkey is provided several times, the last set value is
used.
Example:
curl --pubkey file.pub sftp://example.com/
See also --pass.
-Q, --quote <command>
(FTP SFTP) Send an arbitrary command to the remote FTP or SFTP
server. Quote commands are sent BEFORE the transfer takes place
(just after the initial PWD command in an FTP transfer, to be
exact). To make commands take place after a successful transfer,
prefix them with a dash '-'.
(FTP only) To make commands be sent after curl has changed the
working directory, just before the file transfer command(s),
prefix the command with a '+'. This is not performed when a di-
rectory listing is performed.
You may specify any number of commands.
By default curl stops at first failure. To make curl continue
even if the command fails, prefix the command with an asterisk
(*). Otherwise, if the server returns failure for one of the
commands, the entire operation is aborted.
You must send syntactically correct FTP commands as RFC 959 de-
fines to FTP servers, or one of the commands listed below to
SFTP servers.
SFTP is a binary protocol. Unlike for FTP, curl interprets SFTP
quote commands itself before sending them to the server. File-
names may be quoted shell-style to embed spaces or special char-
acters. Following is the list of all supported SFTP quote com-
mands:
atime date file
The atime command sets the last access time of the file
named by the file operand. The date expression can be all
sorts of date strings, see the curl_getdate(3) man page
for date expression details. (Added in 7.73.0)
chgrp group file
The chgrp command sets the group ID of the file named by
the file operand to the group ID specified by the group
operand. The group operand is a decimal integer group ID.
chmod mode file
The chmod command modifies the file mode bits of the
specified file. The mode operand is an octal integer mode
number.
chown user file
The chown command sets the owner of the file named by the
file operand to the user ID specified by the user oper-
and. The user operand is a decimal integer user ID.
ln source_file target_file
The ln and symlink commands create a symbolic link at the
target_file location pointing to the source_file loca-
tion.
mkdir directory_name
The mkdir command creates the directory named by the di-
rectory_name operand.
mtime date file
The mtime command sets the last modification time of the
file named by the file operand. The date expression can
be all sorts of date strings, see the curl_getdate(3) man
page for date expression details. (Added in 7.73.0)
pwd The pwd command returns the absolute path name of the
current working directory.
rename source target
The rename command renames the file or directory named by
the source operand to the destination path named by the
target operand.
rm file
The rm command removes the file specified by the file op-
erand.
rmdir directory
The rmdir command removes the directory entry specified
by the directory operand, provided it is empty.
symlink source_file target_file
See ln.
--quote can be used several times in a command line
Example:
curl --quote "DELE file" ftp://example.com/foo
See also -X, --request.
--random-file <file>
Deprecated option. This option is ignored (added in 7.84.0).
Prior to that it only had an effect on curl if built to use old
versions of OpenSSL.
Specify the path name to file containing random data. The data
may be used to seed the random engine for SSL connections.
If --random-file is provided several times, the last set value
is used.
Example:
curl --random-file rubbish https://example.com
See also --egd-file.
-r, --range <range>
(HTTP FTP SFTP FILE) Retrieve a byte range (i.e. a partial docu-
ment) from an HTTP/1.1, FTP or SFTP server or a local FILE.
Ranges can be specified in a number of ways.
0-499 specifies the first 500 bytes
500-999
specifies the second 500 bytes
-500 specifies the last 500 bytes
9500- specifies the bytes from offset 9500 and forward
0-0,-1 specifies the first and last byte only(*)(HTTP)
100-199,500-599
specifies two separate 100-byte ranges(*) (HTTP)
(*) = NOTE that if specifying multiple ranges and the server
supports it then it replies with a multiple part response that
curl returns as-is. It contains meta information in addition to
the requested bytes. Parsing or otherwise transforming this re-
sponse is the responsibility of the caller.
Only digit characters (0-9) are valid in the 'start' and 'stop'
fields of the 'start-stop' range syntax. If a non-digit charac-
ter is given in the range, the server's response is unspecified,
depending on the server's configuration.
Many HTTP/1.1 servers do not have this feature enabled, so that
when you attempt to get a range, curl instead gets the whole
document.
FTP and SFTP range downloads only support the simple
'start-stop' syntax (optionally with one of the numbers omit-
ted). FTP use depends on the extended FTP command SIZE.
When using this option for HTTP uploads using POST or PUT, func-
tionality is not guaranteed. The HTTP protocol has no standard
interoperable resume upload and curl uses a set of headers for
this purpose that once proved working for some servers and have
been left for those who find that useful.
This command line option is mutually exclusive with -C, --con-
tinue-at: you can only use one of them for a single transfer.
If --range is provided several times, the last set value is
used.
Example:
curl --range 22-44 https://example.com
See also -C, --continue-at and -a, --append.
--rate <max request rate>
Specify the maximum transfer frequency you allow curl to use -
in number of transfer starts per time unit (sometimes called re-
quest rate). Without this option, curl starts the next transfer
as fast as possible.
If given several URLs and a transfer completes faster than the
allowed rate, curl waits until the next transfer is started to
maintain the requested rate. This option has no effect when -Z,
--parallel is used.
The request rate is provided as "N/U" where N is an integer num-
ber and U is a time unit. Supported units are 's' (second), 'm'
(minute), 'h' (hour) and 'd' /(day, as in a 24 hour unit). The
default time unit, if no "/U" is provided, is number of trans-
fers per hour.
If curl is told to allow 10 requests per minute, it does not
start the next request until 6 seconds have elapsed since the
previous transfer was started.
This function uses millisecond resolution. If the allowed fre-
quency is set more than 1000 per second, it instead runs unre-
stricted.
When retrying transfers, enabled with --retry, the separate
retry delay logic is used and not this setting.
Starting in version 8.10.0, you can specify the number of time
units in the rate expression. Make curl do no more than 5 trans-
fers per 15 seconds with "5/15s" or limit it to 3 transfers per
4 hours with "3/4h". No spaces allowed.
This option is global and does not need to be specified for each
use of --next.
If --rate is provided several times, the last set value is used.
Examples:
curl --rate 2/s https://example.com ...
curl --rate 3/h https://example.com ...
curl --rate 14/m https://example.com ...
Added in 7.84.0. See also --limit-rate and --retry-delay.
--raw (HTTP) When used, it disables all internal HTTP decoding of con-
tent or transfer encodings and instead makes them passed on un-
altered, raw.
Providing --raw multiple times has no extra effect. Disable it
again with --no-raw.
Example:
curl --raw https://example.com
See also --tr-encoding.
-e, --referer <URL>
(HTTP) Set the referrer URL in the HTTP request. This can also
be set with the -H, --header flag of course. When used with -L,
--location you can append ";auto"" to the -e, --referer URL to
make curl automatically set the previous URL when it follows a
Location: header. The ";auto" string can be used alone, even if
you do not set an initial -e, --referer.
If --referer is provided several times, the last set value is
used.
Examples:
curl --referer "https://fake.example" https://example.com
curl --referer "https://fake.example;auto" -L https://example.com
curl --referer ";auto" -L https://example.com
See also -A, --user-agent and -H, --header.
-J, --remote-header-name
(HTTP) Tell the -O, --remote-name option to use the server-spec-
ified Content-Disposition filename instead of extracting a file-
name from the URL. If the server-provided filename contains a
path, that is stripped off before the filename is used.
The file is saved in the current directory, or in the directory
specified with --output-dir.
If the server specifies a filename and a file with that name al-
ready exists in the destination directory, it is not overwritten
and an error occurs - unless you allow it by using the --clobber
option. If the server does not specify a filename then this op-
tion has no effect.
There is no attempt to decode %-sequences (yet) in the provided
filename, so this option may provide you with rather unexpected
filenames.
This feature uses the name from the "filename" field, it does
not yet support the "filename*" field (filenames with explicit
character sets).
WARNING: Exercise judicious use of this option, especially on
Windows. A rogue server could send you the name of a DLL or
other file that could be loaded automatically by Windows or some
third party software.
Providing --remote-header-name multiple times has no extra ef-
fect. Disable it again with --no-remote-header-name.
Example:
curl -OJ https://example.com/file
See also -O, --remote-name.
-O, --remote-name
Write output to a local file named like the remote file we get.
(Only the file part of the remote file is used, the path is cut
off.)
The file is saved in the current working directory. If you want
the file saved in a different directory, make sure you change
the current working directory before invoking curl with this op-
tion or use --output-dir.
The remote filename to use for saving is extracted from the
given URL, nothing else, and if it already exists it is over-
written. If you want the server to be able to choose the file-
name refer to -J, --remote-header-name which can be used in ad-
dition to this option. If the server chooses a filename and that
name already exists it is not overwritten.
There is no URL decoding done on the filename. If it has %20 or
other URL encoded parts of the name, they end up as-is as file-
name.
You may use this option as many times as the number of URLs you
have.
Before curl 8.10.0, curl returned an error if the URL ended with
a slash, which means that there is no filename part in the URL.
Starting in 8.10.0, curl sets the filename to the last directory
part of the URL or if that also is missing to "curl_response"
(without extension) for this situation.
--remote-name is associated with a single URL. Use it once per
URL when you use several URLs in a command line.
Examples:
curl -O https://example.com/filename
curl -O https://example.com/filename -O https://example.com/file2
See also --remote-name-all, --output-dir and -J, --re-
mote-header-name.
--remote-name-all
Change the default action for all given URLs to be dealt with as
if -O, --remote-name were used for each one. If you want to dis-
able that for a specific URL after --remote-name-all has been
used, you must use "-o -" or --no-remote-name.
Providing --remote-name-all multiple times has no extra effect.
Disable it again with --no-remote-name-all.
Example:
curl --remote-name-all ftp://example.com/file1 ftp://example.com/file2
See also -O, --remote-name.
-R, --remote-time
Make curl attempt to figure out the timestamp of the remote file
that is getting downloaded, and if that is available make the
local file get that same timestamp.
Providing --remote-time multiple times has no extra effect.
Disable it again with --no-remote-time.
Example:
curl --remote-time -o foo https://example.com
See also -O, --remote-name and -z, --time-cond.
--remove-on-error
Remove the output file if an error occurs. If curl returns an
error when told to save output in a local file. This prevents
curl from leaving a partial file in the case of an error during
transfer.
If the output is not a regular file, this option has no effect.
The -C, --continue-at option cannot be used together with --re-
move-on-error.
Providing --remove-on-error multiple times has no extra effect.
Disable it again with --no-remove-on-error.
Example:
curl --remove-on-error -o output https://example.com
Added in 7.83.0. See also -f, --fail.
-X, --request <method>
Change the method to use when starting the transfer.
curl passes on the verbatim string you give it in the request
without any filter or other safe guards. That includes white
space and control characters.
HTTP Specifies a custom request method to use when communicat-
ing with the HTTP server. The specified request method is
used instead of the method otherwise used (which defaults
to GET). Read the HTTP 1.1 specification for details and
explanations. Common additional HTTP requests include PUT
and DELETE, while related technologies like WebDAV offers
PROPFIND, COPY, MOVE and more.
Normally you do not need this option. All sorts of GET,
HEAD, POST and PUT requests are rather invoked by using
dedicated command line options.
This option only changes the actual word used in the HTTP
request, it does not alter the way curl behaves. For ex-
ample if you want to make a proper HEAD request, using -X
HEAD does not suffice. You need to use the -I, --head op-
tion.
The method string you set with -X, --request is used for
all requests, which if you for example use -L, --location
may cause unintended side-effects when curl does not
change request method according to the HTTP 30x response
codes - and similar.
FTP Specifies a custom FTP command to use instead of LIST
when doing file lists with FTP.
POP3 Specifies a custom POP3 command to use instead of LIST or
RETR.
IMAP Specifies a custom IMAP command to use instead of LIST.
SMTP Specifies a custom SMTP command to use instead of HELP or
VRFY.
If --request is provided several times, the last set value is
used.
Examples:
curl -X "DELETE" https://example.com
curl -X NLST ftp://example.com/
See also --request-target.
--request-target <path>
(HTTP) Use an alternative target (path) instead of using the
path as provided in the URL. Particularly useful when wanting to
issue HTTP requests without leading slash or other data that
does not follow the regular URL pattern, like "OPTIONS *".
curl passes on the verbatim string you give it in the request
without any filter or other safe guards. That includes white
space and control characters.
If --request-target is provided several times, the last set
value is used.
Example:
curl --request-target "*" -X OPTIONS https://example.com
See also -X, --request.
--resolve <[+]host:port:addr[,addr]...>
Provide a custom address for a specific host and port pair. Us-
ing this, you can make the curl requests(s) use a specified ad-
dress and prevent the otherwise normally resolved address to be
used. Consider it a sort of /etc/hosts alternative provided on
the command line. The port number should be the number used for
the specific protocol the host is used for. It means you need
several entries if you want to provide addresses for the same
host but different ports.
By specifying "*" as host you can tell curl to resolve any host
and specific port pair to the specified address. Wildcard is re-
solved last so any --resolve with a specific host and port is
used first.
The provided address set by this option is used even if -4,
--ipv4 or -6, --ipv6 is set to make curl use another IP version.
By prefixing the host with a '+' you can make the entry time out
after curl's default timeout (1 minute). Note that this only
makes sense for long running parallel transfers with a lot of
files. In such cases, if this option is used curl tries to re-
solve the host as it normally would once the timeout has ex-
pired.
Provide IPv6 addresses within [brackets].
To redirect connects from a specific hostname or any hostname,
independently of port number, consider the --connect-to option.
Support for resolving with wildcard was added in 7.64.0.
Support for the '+' prefix was added in 7.75.0.
Support for specifying the host component as an IPv6 address was
added in 8.13.0.
--resolve can be used several times in a command line
Examples:
curl --resolve example.com:443:127.0.0.1 https://example.com
curl --resolve example.com:443:[2001:db8::252f:efd6] https://example.com
See also --connect-to and --alt-svc.
--retry <num>
If a transient error is returned when curl tries to perform a
transfer, it retries this number of times before giving up. Set-
ting the number to 0 makes curl do no retries (which is the de-
fault). Transient error means either: a timeout, an FTP 4xx re-
sponse code or an HTTP 408, 429, 500, 502, 503 or 504 response
code.
When curl is about to retry a transfer, it first waits one sec-
ond and then for all forthcoming retries it doubles the waiting
time until it reaches 10 minutes, which then remains the set
fixed delay time between the rest of the retries. By using
--retry-delay you disable this exponential backoff algorithm.
See also --retry-max-time to limit the total time allowed for
retries.
curl complies with the Retry-After: response header if one was
present to know when to issue the next retry (added in 7.66.0).
If --retry is provided several times, the last set value is
used.
Example:
curl --retry 7 https://example.com
See also --retry-max-time.
--retry-all-errors
Retry on any error. This option is used together with --retry.
This option is the "sledgehammer" of retrying. Do not use this
option by default (for example in your curlrc), there may be un-
intended consequences such as sending or receiving duplicate
data. Do not use with redirected input or output. You might be
better off handling your unique problems in a shell script.
Please read the example below.
WARNING: For server compatibility curl attempts to retry failed
flaky transfers as close as possible to how they were started,
but this is not possible with redirected input or output. For
example, before retrying it removes output data from a failed
partial transfer that was written to an output file. However
this is not true of data redirected to a | pipe or > file, which
are not reset. We strongly suggest you do not parse or record
output via redirect in combination with this option, since you
may receive duplicate data.
By default curl does not return an error for transfers with an
HTTP response code that indicates an HTTP error, if the transfer
was successful. For example, if a server replies 404 Not Found
and the reply is fully received then that is not an error. When
--retry is used then curl retries on some HTTP response codes
that indicate transient HTTP errors, but that does not include
most 4xx response codes such as 404. If you want to retry on all
response codes that indicate HTTP errors (4xx and 5xx) then com-
bine with -f, --fail.
Providing --retry-all-errors multiple times has no extra effect.
Disable it again with --no-retry-all-errors.
Example:
curl --retry 5 --retry-all-errors https://example.com
Added in 7.71.0. See also --retry.
--retry-connrefused
In addition to the other conditions, consider ECONNREFUSED as a
transient error too for --retry. This option is used together
with --retry.
Providing --retry-connrefused multiple times has no extra ef-
fect. Disable it again with --no-retry-connrefused.
Example:
curl --retry-connrefused --retry 7 https://example.com
See also --retry and --retry-all-errors.
--retry-delay <seconds>
Make curl sleep this amount of time before each retry when a
transfer has failed with a transient error (it changes the de-
fault backoff time algorithm between retries). This option is
only interesting if --retry is also used. Setting this delay to
zero makes curl use the default backoff time.
If --retry-delay is provided several times, the last set value
is used.
Example:
curl --retry-delay 5 --retry 7 https://example.com
See also --retry.
--retry-max-time <seconds>
The retry timer is reset before the first transfer attempt. Re-
tries are done as usual (see --retry) as long as the timer has
not reached this given limit. Notice that if the timer has not
reached the limit, the request is made and while performing, it
may take longer than this given time period. To limit a single
request's maximum time, use -m, --max-time. Set this option to
zero to not timeout retries.
If --retry-max-time is provided several times, the last set
value is used.
Example:
curl --retry-max-time 30 --retry 10 https://example.com
See also --retry.
--sasl-authzid <identity>
Use this authorization identity (authzid), during SASL PLAIN au-
thentication, in addition to the authentication identity (auth-
cid) as specified by -u, --user.
If the option is not specified, the server derives the authzid
from the authcid, but if specified, and depending on the server
implementation, it may be used to access another user's inbox,
that the user has been granted access to, or a shared mailbox
for example.
If --sasl-authzid is provided several times, the last set value
is used.
Example:
curl --sasl-authzid zid imap://example.com/
Added in 7.66.0. See also --login-options.
--sasl-ir
Enable initial response in SASL authentication.
Providing --sasl-ir multiple times has no extra effect. Disable
it again with --no-sasl-ir.
Example:
curl --sasl-ir imap://example.com/
See also --sasl-authzid.
--service-name <name>
Set the service name for SPNEGO.
If --service-name is provided several times, the last set value
is used.
Example:
curl --service-name sockd/server https://example.com
See also --negotiate and --proxy-service-name.
-S, --show-error
When used with -s, --silent, it makes curl show an error message
if it fails.
This option is global and does not need to be specified for each
use of --next.
Providing --show-error multiple times has no extra effect. Dis-
able it again with --no-show-error.
Example:
curl --show-error --silent https://example.com
See also --no-progress-meter.
-i, --show-headers
(HTTP FTP) Show response headers in the output. HTTP response
headers can include things like server name, cookies, date of
the document, HTTP version and more. With non-HTTP protocols,
the "headers" are other server communication.
This option makes the response headers get saved in the same
stream/output as the data. -D, --dump-header exists to save
headers in a separate stream.
To view the request headers, consider the -v, --verbose option.
Prior to 7.75.0 curl did not print the headers if -f, --fail was
used in combination with this option and there was an error re-
ported by the server.
This option was called --include before 8.10.0. The previous
name remains functional.
Providing --show-headers multiple times has no extra effect.
Disable it again with --no-show-headers.
Example:
curl -i https://example.com
See also -v, --verbose and -D, --dump-header.
--sigalgs <list>
(TLS) Set specific signature algorithms to use during SSL ses-
sion establishment according to RFC 5246, 7.4.1.4.1.
An algorithm can use either a signature algorithm and a hash al-
gorithm pair separated by a "+" (e.g. "ECDSA+SHA224"), or its
TLS 1.3 signature scheme name (e.g. "ed25519").
Multiple algorithms can be provided by separating them with ":"
(e.g. "DSA+SHA256:rsa_pss_pss_sha256"). The parameter is avail-
able as "-sigalgs" in the OpenSSL "s_client" and "s_server"
utilities.
"--sigalgs" allows a OpenSSL powered curl to make SSL-connec-
tions with exactly the signature algorithms requested by the
client, avoiding nontransparent client/server negotiations.
If this option is set, the default signature algorithm list
built into OpenSSL are ignored.
If --sigalgs is provided several times, the last set value is
used.
Example:
curl --sigalgs ecdsa_secp256r1_sha256 https://example.com
Added in 8.14.0. See also --ciphers.
-s, --silent
Silent or quiet mode. Do not show progress meter or error mes-
sages. Makes curl mute. It still outputs the data you ask for,
potentially even to the terminal/stdout unless you redirect it.
Use -S, --show-error in addition to this option to disable
progress meter but still show error messages.
Providing --silent multiple times has no extra effect. Disable
it again with --no-silent.
Example:
curl -s https://example.com
See also -v, --verbose, --stderr and --no-progress-meter.
--skip-existing
If there is a local file present when a download is requested,
the operation is skipped. Note that curl cannot know if the lo-
cal file was previously downloaded fine, or if it is incomplete
etc, it just knows if there is a filename present in the file
system or not and it skips the transfer if it is.
Providing --skip-existing multiple times has no extra effect.
Disable it again with --no-skip-existing.
Example:
curl --skip-existing --output local/dir/file https://example.com
Added in 8.10.0. See also -o, --output, -O, --remote-name and
--no-clobber.
--socks4 <host[:port]>
Use the specified SOCKS4 proxy. If the port number is not speci-
fied, it is assumed at port 1080. Using this socket type makes
curl resolve the hostname and pass the address on to the proxy.
To specify proxy on a Unix domain socket, use localhost for
host, e.g. "socks4://localhost/path/to/socket.sock"
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
This option is superfluous since you can specify a socks4 proxy
with -x, --proxy using a socks4:// protocol prefix.
--preproxy can be used to specify a SOCKS proxy at the same time
proxy is used with an HTTP/HTTPS proxy. In such a case, curl
first connects to the SOCKS proxy and then connects (through
SOCKS) to the HTTP or HTTPS proxy.
If --socks4 is provided several times, the last set value is
used.
Example:
curl --socks4 hostname:4096 https://example.com
See also --socks4a, --socks5 and --socks5-hostname.
--socks4a <host[:port]>
Use the specified SOCKS4a proxy. If the port number is not spec-
ified, it is assumed at port 1080. This asks the proxy to re-
solve the hostname.
To specify proxy on a Unix domain socket, use localhost for
host, e.g. "socks4a://localhost/path/to/socket.sock"
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
This option is superfluous since you can specify a socks4a proxy
with -x, --proxy using a socks4a:// protocol prefix.
--preproxy can be used to specify a SOCKS proxy at the same time
-x, --proxy is used with an HTTP/HTTPS proxy. In such a case,
curl first connects to the SOCKS proxy and then connects
(through SOCKS) to the HTTP or HTTPS proxy.
If --socks4a is provided several times, the last set value is
used.
Example:
curl --socks4a hostname:4096 https://example.com
See also --socks4, --socks5 and --socks5-hostname.
--socks5 <host[:port]>
Use the specified SOCKS5 proxy - but resolve the hostname lo-
cally. If the port number is not specified, it is assumed at
port 1080.
To specify proxy on a Unix domain socket, use localhost for
host, e.g. "socks5://localhost/path/to/socket.sock"
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
This option is superfluous since you can specify a socks5 proxy
with -x, --proxy using a socks5:// protocol prefix.
--preproxy can be used to specify a SOCKS proxy at the same time
-x, --proxy is used with an HTTP/HTTPS proxy. In such a case,
curl first connects to the SOCKS proxy and then connects
(through SOCKS) to the HTTP or HTTPS proxy.
This option does not work with FTPS or LDAP.
If --socks5 is provided several times, the last set value is
used.
Example:
curl --socks5 proxy.example:7000 https://example.com
See also --socks5-hostname and --socks4a.
--socks5-basic
Use username/password authentication when connecting to a SOCKS5
proxy. The username/password authentication is enabled by de-
fault. Use --socks5-gssapi to force GSS-API authentication to
SOCKS5 proxies.
Providing --socks5-basic multiple times has no extra effect.
Example:
curl --socks5-basic --socks5 hostname:4096 https://example.com
See also --socks5.
--socks5-gssapi
Use GSS-API authentication when connecting to a SOCKS5 proxy.
The GSS-API authentication is enabled by default (if curl is
compiled with GSS-API support). Use --socks5-basic to force
username/password authentication to SOCKS5 proxies.
Providing --socks5-gssapi multiple times has no extra effect.
Disable it again with --no-socks5-gssapi.
Example:
curl --socks5-gssapi --socks5 hostname:4096 https://example.com
See also --socks5.
--socks5-gssapi-nec
As part of the GSS-API negotiation a protection mode is negoti-
ated. RFC 1961 says in section 4.3/4.4 it should be protected,
but the NEC reference implementation does not. The option
--socks5-gssapi-nec allows the unprotected exchange of the pro-
tection mode negotiation.
Providing --socks5-gssapi-nec multiple times has no extra ef-
fect. Disable it again with --no-socks5-gssapi-nec.
Example:
curl --socks5-gssapi-nec --socks5 hostname:4096 https://example.com
See also --socks5.
--socks5-gssapi-service <name>
Set the service name for a socks server. Default is
rcmd/server-fqdn.
If --socks5-gssapi-service is provided several times, the last
set value is used.
Example:
curl --socks5-gssapi-service sockd --socks5 hostname:4096 https://example.com
See also --socks5.
--socks5-hostname <host[:port]>
Use the specified SOCKS5 proxy (and let the proxy resolve the
hostname). If the port number is not specified, it is assumed at
port 1080.
To specify proxy on a Unix domain socket, use localhost for
host, e.g. "socks5h://localhost/path/to/socket.sock"
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
This option is superfluous since you can specify a socks5 host-
name proxy with -x, --proxy using a socks5h:// protocol prefix.
--preproxy can be used to specify a SOCKS proxy at the same time
-x, --proxy is used with an HTTP/HTTPS proxy. In such a case,
curl first connects to the SOCKS proxy and then connects
(through SOCKS) to the HTTP or HTTPS proxy.
If --socks5-hostname is provided several times, the last set
value is used.
Example:
curl --socks5-hostname proxy.example:7000 https://example.com
See also --socks5 and --socks4a.
-Y, --speed-limit <speed>
If a transfer is slower than this set speed (in bytes per sec-
ond) for a given number of seconds, it gets aborted. The time
period is set with -y, --speed-time and is 30 seconds by de-
fault.
If --speed-limit is provided several times, the last set value
is used.
Example:
curl --speed-limit 300 --speed-time 10 https://example.com
See also -y, --speed-time, --limit-rate and -m, --max-time.
-y, --speed-time <seconds>
If a transfer runs slower than speed-limit bytes per second dur-
ing a speed-time period, the transfer is aborted. If speed-time
is used, the default speed-limit is 1 unless set with -Y,
--speed-limit.
This option controls transfers (in both directions) but does not
affect slow connects etc. If this is a concern for you, try the
--connect-timeout option.
If --speed-time is provided several times, the last set value is
used.
Example:
curl --speed-limit 300 --speed-time 10 https://example.com
See also -Y, --speed-limit and --limit-rate.
--ssl (FTP IMAP POP3 SMTP LDAP) Warning: this is considered an inse-
cure option. Consider using --ssl-reqd instead to be sure curl
upgrades to a secure connection.
Try to use SSL/TLS for the connection - often referred to as
STARTTLS or STLS because of the involved commands. Reverts to a
non-secure connection if the server does not support SSL/TLS.
See also --ftp-ssl-control and --ssl-reqd for different levels
of encryption required.
This option is handled in LDAP (added in 7.81.0). It is fully
supported by the OpenLDAP backend and ignored by the generic
ldap backend.
Please note that a server may close the connection if the nego-
tiation does not succeed.
This option was formerly known as --ftp-ssl. That option name
can still be used but might be removed in a future version.
Providing --ssl multiple times has no extra effect. Disable it
again with --no-ssl.
Example:
curl --ssl pop3://example.com/
See also --ssl-reqd, -k, --insecure and --ciphers.
--ssl-allow-beast
(TLS) Do not work around a security flaw in the TLS1.0 protocol
known as BEAST. If this option is not used, the TLS layer may
use workarounds known to cause interoperability problems with
some older server implementations.
This option only changes how curl does TLS 1.0 and has no effect
on later TLS versions.
WARNING: this option loosens the TLS security, and by using this
flag you ask for exactly that.
Providing --ssl-allow-beast multiple times has no extra effect.
Disable it again with --no-ssl-allow-beast.
Example:
curl --ssl-allow-beast https://example.com
See also --proxy-ssl-allow-beast and -k, --insecure.
--ssl-auto-client-cert
(TLS) (Schannel) Automatically locate and use a client certifi-
cate for authentication, when requested by the server. Since the
server can request any certificate that supports client authen-
tication in the OS certificate store it could be a privacy vio-
lation and unexpected.
Providing --ssl-auto-client-cert multiple times has no extra ef-
fect. Disable it again with --no-ssl-auto-client-cert.
Example:
curl --ssl-auto-client-cert https://example.com
Added in 7.77.0. See also --proxy-ssl-auto-client-cert.
--ssl-no-revoke
(TLS) (Schannel) Disable certificate revocation checks. WARNING:
this option loosens the SSL security, and by using this flag you
ask for exactly that.
Providing --ssl-no-revoke multiple times has no extra effect.
Disable it again with --no-ssl-no-revoke.
Example:
curl --ssl-no-revoke https://example.com
See also --crlfile.
--ssl-reqd
(FTP IMAP POP3 SMTP LDAP) Require SSL/TLS for the connection -
often referred to as STARTTLS or STLS because of the involved
commands. Terminates the connection if the transfer cannot be
upgraded to use SSL/TLS.
This option is handled in LDAP (added in 7.81.0). It is fully
supported by the OpenLDAP backend and rejected by the generic
ldap backend if explicit TLS is required.
This option is unnecessary if you use a URL scheme that in it-
self implies immediate and implicit use of TLS, like for FTPS,
IMAPS, POP3S, SMTPS and LDAPS. Such a transfer always fails if
the TLS handshake does not work.
This option was formerly known as --ftp-ssl-reqd.
Providing --ssl-reqd multiple times has no extra effect. Dis-
able it again with --no-ssl-reqd.
Example:
curl --ssl-reqd ftp://example.com
See also --ssl and -k, --insecure.
--ssl-revoke-best-effort
(TLS) (Schannel) Ignore certificate revocation checks when they
failed due to missing/offline distribution points for the revo-
cation check lists.
Providing --ssl-revoke-best-effort multiple times has no extra
effect. Disable it again with --no-ssl-revoke-best-effort.
Example:
curl --ssl-revoke-best-effort https://example.com
Added in 7.70.0. See also --crlfile and -k, --insecure.
--ssl-sessions <filename>
(TLS) Use the given file to load SSL session tickets into curl's
cache before starting any transfers. At the end of a successful
curl run, the cached SSL sessions tickets are saved to the file,
replacing any previous content.
The file does not have to exist, but curl reports an error if it
is unable to create it. Unused loaded tickets are saved again,
unless they get replaced or purged from the cache for space rea-
sons.
Using a session file allows "--tls-earlydata" to send the first
request in "0-RTT" mode, should an SSL session with the feature
be found. Note that a server may not support early data. Also
note that early data does not provide forward secrecy, e.g. is
not as secure.
The SSL session tickets are stored as base64 encoded text, each
ticket on its own line. The hostnames are cryptographically
salted and hashed. While this prevents someone from easily see-
ing the hosts you contacted, they could still check if a spe-
cific hostname matches one of the values.
If --ssl-sessions is provided several times, the last set value
is used.
Example:
curl --ssl-sessions sessions.txt https://example.com
Added in 8.12.0. See also --tls-earlydata.
-2, --sslv2
(SSL) This option previously asked curl to use SSLv2, but is now
ignored (added in 7.77.0). SSLv2 is widely considered insecure
(see RFC 6176).
Providing --sslv2 multiple times has no extra effect.
Example:
curl --sslv2 https://example.com
-2, --sslv2 requires that libcurl is built to support TLS. This
option is mutually exclusive with -3, --sslv3, -1, --tlsv1,
--tlsv1.1 and --tlsv1.2. See also --http1.1 and --http2.
-3, --sslv3
(SSL) This option previously asked curl to use SSLv3, but is now
ignored (added in 7.77.0). SSLv3 is widely considered insecure
(see RFC 7568).
Providing --sslv3 multiple times has no extra effect.
Example:
curl --sslv3 https://example.com
-3, --sslv3 requires that libcurl is built to support TLS. This
option is mutually exclusive with -2, --sslv2, -1, --tlsv1,
--tlsv1.1 and --tlsv1.2. See also --http1.1 and --http2.
--stderr <file>
Redirect all writes to stderr to the specified file instead. If
the filename is a plain '-', it is instead written to stdout.
This option is global and does not need to be specified for each
use of --next.
If --stderr is provided several times, the last set value is
used.
Example:
curl --stderr output.txt https://example.com
See also -v, --verbose and -s, --silent.
--styled-output
Enable automatic use of bold font styles when writing HTTP head-
ers to the terminal. Use --no-styled-output to switch them off.
Styled output requires a terminal that supports bold fonts. This
feature is not present on curl for Windows due to lack of this
capability.
This option is global and does not need to be specified for each
use of --next.
Providing --styled-output multiple times has no extra effect.
Disable it again with --no-styled-output.
Example:
curl --styled-output -I https://example.com
Added in 7.61.0. See also -I, --head and -v, --verbose.
--suppress-connect-headers
When -p, --proxytunnel is used and a CONNECT request is made, do
not output proxy CONNECT response headers. This option is meant
to be used with -D, --dump-header or -i, --show-headers which
are used to show protocol headers in the output. It has no ef-
fect on debug options such as -v, --verbose or --trace, or any
statistics.
Providing --suppress-connect-headers multiple times has no extra
effect. Disable it again with --no-suppress-connect-headers.
Example:
curl --suppress-connect-headers --show-headers -x proxy https://example.com
See also -D, --dump-header, -i, --show-headers and -p, --proxy-
tunnel.
--tcp-fastopen
Enable use of TCP Fast Open (RFC 7413). TCP Fast Open is a TCP
extension that allows data to be sent earlier over the connec-
tion (before the final handshake ACK) if the client and server
have been connected previously.
Providing --tcp-fastopen multiple times has no extra effect.
Disable it again with --no-tcp-fastopen.
Example:
curl --tcp-fastopen https://example.com
See also --false-start.
--tcp-nodelay
Turn on the TCP_NODELAY option. See the curl_easy_setopt(3) man
page for details about this option.
curl sets this option by default and you need to explicitly
switch it off if you do not want it on.
Providing --tcp-nodelay multiple times has no extra effect.
Disable it again with --no-tcp-nodelay.
Example:
curl --tcp-nodelay https://example.com
See also -N, --no-buffer.
-t, --telnet-option <opt=val>
Pass options to the telnet protocol. Supported options are:
TTYPE=<term>
Sets the terminal type.
XDISPLOC=<X display>
Sets the X display location.
NEW_ENV=<var,val>
Sets an environment variable.
--telnet-option can be used several times in a command line
Example:
curl -t TTYPE=vt100 telnet://example.com/
See also -K, --config.
--tftp-blksize <value>
(TFTP) Set the TFTP BLKSIZE option (must be 512 or larger). This
is the block size that curl tries to use when transferring data
to or from a TFTP server. By default 512 bytes are used.
If --tftp-blksize is provided several times, the last set value
is used.
Example:
curl --tftp-blksize 1024 tftp://example.com/file
See also --tftp-no-options.
--tftp-no-options
(TFTP) Do not send TFTP options requests. This improves interop
with some legacy servers that do not acknowledge or properly im-
plement TFTP options. When this option is used --tftp-blksize is
ignored.
Providing --tftp-no-options multiple times has no extra effect.
Disable it again with --no-tftp-no-options.
Example:
curl --tftp-no-options tftp://192.168.0.1/
See also --tftp-blksize.
-z, --time-cond <time>
(HTTP FTP) Request a file that has been modified later than the
given time and date, or one that has been modified before that
time. The date expression can be all sorts of date strings or if
it does not match any internal ones, it is treated as a filename
and curl tries to get the modification date (mtime) from that
file instead. See the curl_getdate(3) man pages for date expres-
sion details.
Start the date expression with a dash (-) to make it request for
a document that is older than the given date/time, default is a
document that is newer than the specified date/time.
If provided a non-existing file, curl outputs a warning about
that fact and proceeds to do the transfer without a time condi-
tion.
If --time-cond is provided several times, the last set value is
used.
Examples:
curl -z "Wed 01 Sep 2021 12:18:00" https://example.com
curl -z "-Wed 01 Sep 2021 12:18:00" https://example.com
curl -z file https://example.com
See also --etag-compare and -R, --remote-time.
--tls-earlydata
(TLS) Enable the use of TLSv1.3 early data, also known as '0RTT'
where possible. This has security implications for the requests
sent that way.
This option is used when curl is built to use GnuTLS.
If a server supports this TLSv1.3 feature, and to what extent,
is announced as part of the TLS "session" sent back to curl. Un-
til curl has seen such a session in a previous request, early
data cannot be used.
When a new connection is initiated with a known TLSv1.3 session,
and that session announced early data support, the first request
on this connection is sent before the TLS handshake is complete.
While the early data is also encrypted, it is not protected
against replays. An attacker can send your early data to the
server again and the server would accept it.
If your request contacts a public server and only retrieves a
file, there may be no harm in that. If the first request orders
a refrigerator for you, it is probably not a good idea to use
early data for it. curl cannot deduce what the security implica-
tions of your requests actually are and make this decision for
you.
The amount of early data sent can be inspected by using the "-w,
--write-out" variable "tls_earlydata".
WARNING: this option has security implications. See above for
more details.
Providing --tls-earlydata multiple times has no extra effect.
Disable it again with --no-tls-earlydata.
Example:
curl --tls-earlydata https://example.com
Added in 8.11.0. See also --tlsv1.3, --tls-max and --ssl-ses-
sions.
--tls-max <VERSION>
(TLS) Set the maximum allowed TLS version. The minimum accept-
able version is set by tlsv1.0, tlsv1.1, tlsv1.2 or tlsv1.3.
If the connection is done without TLS, this option has no ef-
fect. This includes QUIC-using (HTTP/3) transfers.
default
Use up to the recommended TLS version.
1.0 Use up to TLSv1.0.
1.1 Use up to TLSv1.1.
1.2 Use up to TLSv1.2.
1.3 Use up to TLSv1.3.
If --tls-max is provided several times, the last set value is
used.
Examples:
curl --tls-max 1.2 https://example.com
curl --tls-max 1.3 --tlsv1.2 https://example.com
--tls-max requires that libcurl is built to support TLS. See
also --tlsv1.0, --tlsv1.1, --tlsv1.2 and --tlsv1.3.
--tls13-ciphers <list>
(TLS) Set which cipher suites to use in the connection if it ne-
gotiates TLS 1.3. The list of ciphers suites must specify valid
ciphers. Read up on TLS 1.3 cipher suite details on this URL:
https://curl.se/docs/ssl-ciphers.html
This option is used when curl is built to use OpenSSL 1.1.1 or
later, wolfSSL, or mbedTLS 3.6.0 or later.
Before curl 8.10.0 with mbedTLS or wolfSSL, TLS 1.3 cipher
suites were set by using the --ciphers option.
If --tls13-ciphers is provided several times, the last set value
is used.
Example:
curl --tls13-ciphers TLS_AES_128_GCM_SHA256 https://example.com
Added in 7.61.0. See also --ciphers, --proxy-tls13-ciphers and
--curves.
--tlsauthtype <type>
(TLS) Set TLS authentication type. Currently, the only supported
option is "SRP", for TLS-SRP (RFC 5054). If --tlsuser and
--tlspassword are specified but --tlsauthtype is not, then this
option defaults to "SRP". This option works only if the underly-
ing libcurl is built with TLS-SRP support, which requires
OpenSSL or GnuTLS with TLS-SRP support.
If --tlsauthtype is provided several times, the last set value
is used.
Example:
curl --tlsauthtype SRP https://example.com
See also --tlsuser.
--tlspassword <string>
(TLS) Set password to use with the TLS authentication method
specified with --tlsauthtype. Requires that --tlsuser is set.
This option does not work with TLS 1.3.
If --tlspassword is provided several times, the last set value
is used.
Example:
curl --tlspassword pwd --tlsuser user https://example.com
See also --tlsuser.
--tlsuser <name>
(TLS) Set username for use with the TLS authentication method
specified with --tlsauthtype. Requires that --tlspassword also
is set.
This option does not work with TLS 1.3.
If --tlsuser is provided several times, the last set value is
used.
Example:
curl --tlspassword pwd --tlsuser user https://example.com
See also --tlspassword.
-1, --tlsv1
(TLS) Use at least TLS version 1.x when negotiating with a re-
mote TLS server. That means TLS version 1.0 or higher
Providing --tlsv1 multiple times has no extra effect.
Example:
curl --tlsv1 https://example.com
-1, --tlsv1 requires that libcurl is built to support TLS. This
option is mutually exclusive with --tlsv1.1, --tlsv1.2 and
--tlsv1.3. See also --http1.1 and --http2.
--tlsv1.0
(TLS) Force curl to use TLS version 1.0 or later when connecting
to a remote TLS server.
In old versions of curl this option was documented to allow
_only_ TLS 1.0. That behavior was inconsistent depending on the
TLS library. Use --tls-max if you want to set a maximum TLS ver-
sion.
Providing --tlsv1.0 multiple times has no extra effect.
Example:
curl --tlsv1.0 https://example.com
See also --tlsv1.3.
--tlsv1.1
(TLS) Force curl to use TLS version 1.1 or later when connecting
to a remote TLS server.
In old versions of curl this option was documented to allow
_only_ TLS 1.1. That behavior was inconsistent depending on the
TLS library. Use --tls-max if you want to set a maximum TLS ver-
sion.
Providing --tlsv1.1 multiple times has no extra effect.
Example:
curl --tlsv1.1 https://example.com
See also --tlsv1.3 and --tls-max.
--tlsv1.2
(TLS) Force curl to use TLS version 1.2 or later when connecting
to a remote TLS server.
In old versions of curl this option was documented to allow
_only_ TLS 1.2. That behavior was inconsistent depending on the
TLS library. Use --tls-max if you want to set a maximum TLS ver-
sion.
Providing --tlsv1.2 multiple times has no extra effect.
Example:
curl --tlsv1.2 https://example.com
See also --tlsv1.3 and --tls-max.
--tlsv1.3
(TLS) Force curl to use TLS version 1.3 or later when connecting
to a remote TLS server.
If the connection is done without TLS, this option has no ef-
fect. This includes QUIC-using (HTTP/3) transfers.
Note that TLS 1.3 is not supported by all TLS backends.
Providing --tlsv1.3 multiple times has no extra effect.
Example:
curl --tlsv1.3 https://example.com
See also --tlsv1.2 and --tls-max.
--tr-encoding
(HTTP) Request a compressed Transfer-Encoding response using one
of the algorithms curl supports, and uncompress the data while
receiving it.
Providing --tr-encoding multiple times has no extra effect.
Disable it again with --no-tr-encoding.
Example:
curl --tr-encoding https://example.com
See also --compressed.
--trace <file>
Save a full trace dump of all incoming and outgoing data, in-
cluding descriptive information, in the given output file. Use
"-" as filename to have the output sent to stdout. Use "%" as
filename to have the output sent to stderr.
Note that verbose output of curl activities and network traffic
might contain sensitive data, including usernames, credentials
or secret data content. Be aware and be careful when sharing
trace logs with others.
This option is global and does not need to be specified for each
use of --next.
If --trace is provided several times, the last set value is
used.
Example:
curl --trace log.txt https://example.com
This option is mutually exclusive with -v, --verbose and
--trace-ascii. See also --trace-ascii, --trace-config,
--trace-ids and --trace-time.
--trace-ascii <file>
Save a full trace dump of all incoming and outgoing data, in-
cluding descriptive information, in the given output file. Use
"-" as filename to have the output sent to stdout. Use "%" as
filename to send the output to stderr.
This is similar to --trace, but leaves out the hex part and only
shows the ASCII part of the dump. It makes smaller output that
might be easier to read for untrained humans.
Note that verbose output of curl activities and network traffic
might contain sensitive data, including usernames, credentials
or secret data content. Be aware and be careful when sharing
trace logs with others.
This option is global and does not need to be specified for each
use of --next.
If --trace-ascii is provided several times, the last set value
is used.
Example:
curl --trace-ascii log.txt https://example.com
This option is mutually exclusive with --trace and -v, --ver-
bose. See also -v, --verbose and --trace.
--trace-config <string>
Set configuration for trace output. A comma-separated list of
components where detailed output can be made available from.
Names are case-insensitive. Specify 'all' to enable all trace
components.
In addition to trace component names, specify "ids" and "time"
to avoid extra --trace-ids or --trace-time parameters.
See the curl_global_trace(3) man page for more details.
This option is global and does not need to be specified for each
use of --next.
--trace-config can be used several times in a command line
Example:
curl --trace-config ids,http/2 https://example.com
Added in 8.3.0. See also -v, --verbose and --trace.
--trace-ids
Prepend the transfer and connection identifiers to each trace or
verbose line that curl displays.
This option is global and does not need to be specified for each
use of --next.
Providing --trace-ids multiple times has no extra effect. Dis-
able it again with --no-trace-ids.
Example:
curl --trace-ids --trace-ascii output https://example.com
Added in 8.2.0. See also --trace and -v, --verbose.
--trace-time
Prepend a time stamp to each trace or verbose line that curl
displays.
This option is global and does not need to be specified for each
use of --next.
Providing --trace-time multiple times has no extra effect. Dis-
able it again with --no-trace-time.
Example:
curl --trace-time --trace-ascii output https://example.com
See also --trace and -v, --verbose.
--unix-socket <path>
(HTTP) Connect through this Unix domain socket, instead of using
the network.
If --unix-socket is provided several times, the last set value
is used.
Example:
curl --unix-socket socket-path https://example.com
See also --abstract-unix-socket.
-T, --upload-file <file>
Upload the specified local file to the remote URL.
If there is no file part in the specified URL, curl appends the
local file name to the end of the URL before the operation
starts. You must use a trailing slash (/) on the last directory
to prove to curl that there is no filename or curl thinks that
your last directory name is the remote filename to use.
When putting the local filename at the end of the URL, curl ig-
nores what is on the left side of any slash (/) or backslash
(\\) used in the filename and only appends what is on the right
side of the rightmost such character.
Use the filename "-" (a single dash) to use stdin instead of a
given file. Alternately, the filename "." (a single period) may
be specified instead of "-" to use stdin in non-blocking mode to
allow reading server output while stdin is being uploaded.
If this option is used with an HTTP(S) URL, the PUT method is
used.
You can specify one -T, --upload-file for each URL on the com-
mand line. Each -T, --upload-file + URL pair specifies what to
upload and to where. curl also supports globbing of the -T,
--upload-file argument, meaning that you can upload multiple
files to a single URL by using the same URL globbing style sup-
ported in the URL.
When uploading to an SMTP server: the uploaded data is assumed
to be RFC 5322 formatted. It has to feature the necessary set of
headers and mail body formatted correctly by the user as curl
does not transcode nor encode it further in any way.
--upload-file is associated with a single URL. Use it once per
URL when you use several URLs in a command line.
Examples:
curl -T file https://example.com
curl -T "img[1-1000].png" ftp://ftp.example.com/
curl --upload-file "{file1,file2}" https://example.com
curl -T file -T file2 https://example.com https://example.com
See also -G, --get, -I, --head, -X, --request and -d, --data.
--upload-flags <flags>
Specify additional behavior to apply to uploaded files. Flags
are specified as either a single flag value or a comma-separated
list of flag values. These values are case-sensitive and may be
negated by prepending them with a '-' character. Currently the
following flag values are accepted: answered, deleted, draft,
flagged, and seen. The currently-accepted flag values are used
to set flags on IMAP uploads.
If --upload-flags is provided several times, the last set value
is used.
Example:
curl --upload-flags Flagged,!Seen --upload-file local/dir/file https://example.com
Added in 8.13.0. See also -T, --upload-file.
--url <url/file>
Specify a URL to fetch or send data to.
If the given URL is missing a scheme (such as "http://" or
"ftp://" etc) curl guesses which scheme to use based on the
hostname. If the outermost subdomain name matches DICT, FTP,
IMAP, LDAP, POP3 or SMTP case insensitively, then that protocol
is used, otherwise it assumes HTTP. Scheme guessing can be
avoided by providing a full URL including the scheme, or dis-
abled by setting a default protocol, see --proto-default for de-
tails.
To control where the contents of a retrieved URL is written in-
stead of the default stdout, use the -o, --output or the -O,
--remote-name options. When retrieving multiple URLs in a single
invoke, each provided URL needs its own dedicated destination
option unless --remote-name-all is used.
On Windows, "file://" accesses can be converted to network ac-
cesses by the operating system.
Starting in curl 8.13.0, curl can be told to download URLs pro-
vided in a text file, one URL per line. It is done with "--url
@filename": so instead of a URL, you specify a filename prefixed
with the "@" symbol. It can be told to load the list of URLs
from stdin by providing an argument like "@-".
When downloading URLs given in a file, it implies using -O,
--remote-name for each provided URL. The URLs are full, there is
no globbing applied or done on these. Features such as
--skip-existing work fine in combination with this.
Lines in the URL file that start with "#" are treated as com-
ments and are skipped.
--url can be used several times in a command line
Examples:
curl --url https://example.com
curl --url @file
See also -:, --next, -K, --config, --path-as-is and --disal-
low-username-in-url.
--url-query <data>
(all) Add a piece of data, usually a name + value pair, to the
end of the URL query part. The syntax is identical to that used
for --data-urlencode with one extension:
If the argument starts with a '+' (plus), the rest of the string
is provided as-is unencoded.
The query part of a URL is the one following the question mark
on the right end.
--url-query can be used several times in a command line
Examples:
curl --url-query name=val https://example.com
curl --url-query =encodethis http://example.net/foo
curl --url-query name@file https://example.com
curl --url-query @fileonly https://example.com
curl --url-query "+name=%20foo" https://example.com
Added in 7.87.0. See also --data-urlencode and -G, --get.
-B, --use-ascii
(FTP LDAP) Enable ASCII transfer mode. For FTP, this can also be
enforced by using a URL that ends with ";type=A". This option
causes data sent to stdout to be in text mode for Win32 systems.
Providing --use-ascii multiple times has no extra effect. Dis-
able it again with --no-use-ascii.
Example:
curl -B ftp://example.com/README
See also --crlf and --data-ascii.
-u, --user <user:password>
Specify the username and password to use for server authentica-
tion. Overrides -n, --netrc and --netrc-optional.
If you simply specify the username, curl prompts for a password.
The username and passwords are split up on the first colon,
which makes it impossible to use a colon in the username with
this option. The password can, still.
On systems where it works, curl hides the given option argument
from process listings. This is not enough to protect credentials
from possibly getting seen by other users on the same system as
they still are visible for a moment before being cleared. Such
sensitive data should be retrieved from a file instead or simi-
lar and never used in clear text in a command line.
When using Kerberos V5 with a Windows based server you should
include the Windows domain name in the username, in order for
the server to successfully obtain a Kerberos Ticket. If you do
not, then the initial authentication handshake may fail.
When using NTLM, the username can be specified simply as the
username, without the domain, if there is a single domain and
forest in your setup for example.
To specify the domain name use either Down-Level Logon Name or
UPN (User Principal Name) formats. For example, EXAMPLE\user and
user@example.com respectively.
If you use a Windows SSPI-enabled curl binary and perform Ker-
beros V5, Negotiate, NTLM or Digest authentication then you can
tell curl to select the username and password from your environ-
ment by specifying a single colon with this option: "-u :".
If --user is provided several times, the last set value is used.
Example:
curl -u user:secret https://example.com
See also -n, --netrc and -K, --config.
-A, --user-agent <name>
(HTTP) Specify the User-Agent string to send to the HTTP server.
To encode blanks in the string, surround the string with single
quote marks. This header can also be set with the -H, --header
or the --proxy-header options.
If you give an empty argument to -A, --user-agent (""), it re-
moves the header completely from the request. If you prefer a
blank header, you can set it to a single space (" ").
By default, curl uses curl/VERSION, such as User-Agent:
curl/8.14.1.
If --user-agent is provided several times, the last set value is
used.
Example:
curl -A "Agent 007" https://example.com
See also -H, --header and --proxy-header.
--variable <[%]name=text/@file>
Set a variable with "name=content" or "name@file" (where "file"
can be stdin if set to a single dash ("-")). The name is a case
sensitive identifier that must consist of no other letters than
a-z, A-Z, 0-9 or underscore. The specified content is then asso-
ciated with this identifier.
Setting the same variable name again overwrites the old contents
with the new.
The contents of a variable can be referenced in a later command
line option when that option name is prefixed with "--expand-",
and the name is used as "{{name}}".
--variable can import environment variables into the name space.
Opt to either require the environment variable to be set or pro-
vide a default value for the variable in case it is not already
set.
--variable %name imports the variable called "name" but exits
with an error if that environment variable is not already set.
To provide a default value if the environment variable is not
set, use --variable %name=content or --variable %name@content.
Note that on some systems - but not all - environment variables
are case insensitive.
Added in curl 8.12.0: you can get a byte range from the source
by appending "[start-end]" to the variable name, where start and
end are byte offsets to include from the contents. For example,
asking for offset "2-10" means offset two to offset ten, inclu-
sive, resulting in 9 bytes in total. "2-2" means a single byte
at offset 2. Not providing a second number implies to the end of
data. The start offset cannot be larger than the end offset.
Asking for a range that is outside of the file size makes the
variable contents empty. For example, getting the first one
hundred bytes from a given file:
curl --variable "fraction[0-99]@filename"
Given a byte range that has no data results in an empty string.
Asking for a range that is larger than the content makes curl
use the piece of the data that exists.
To assign a variable using contents from another variable, use
--expand-variable. Like for example assigning a new variable us-
ing contents from two other:
curl --expand-variable "user={{firstname}} {{lastname}}"
When expanding variables, curl supports a set of functions that
can make the variable contents more convenient to use. You apply
a function to a variable expansion by adding a colon and then
list the desired functions in a comma-separated list that is
evaluated in a left-to-right order. Variable content holding
null bytes that are not encoded when expanded causes an error.
Available functions:
trim removes all leading and trailing white space.
Example:
curl --expand-url https://example.com/{{var:trim}}
json outputs the content using JSON string quoting rules.
Example:
curl --expand-data {{data:json}} https://example.com
url shows the content URL (percent) encoded.
Example:
curl --expand-url https://example.com/{{path:url}}
b64 expands the variable base64 encoded
Example:
curl --expand-url https://example.com/{{var:b64}}
64dec decodes a base64 encoded character sequence. If the se-
quence is not possible to decode, it instead outputs
"[64dec-fail]"
Example:
curl --expand-url https://example.com/{{var:64dec}}
(Added in 8.13.0)
--variable can be used several times in a command line
Example:
curl --variable name=smith --expand-url "https://example.com/{{name}}"
Added in 8.3.0. See also -K, --config.
-v, --verbose
Make curl output verbose information during the operation. Use-
ful for debugging and seeing what's going on under the hood. A
line starting with > means header data sent by curl, < means
header data received by curl that is hidden in normal cases, and
a line starting with * means additional info provided by curl.
If you only want HTTP headers in the output, -i, --show-headers
or -D, --dump-header might be more suitable options.
Since curl 8.10, mentioning this option several times in the
same argument increases the level of the trace output. However,
as before, a single -v, --verbose or --no-verbose reverts any
additions by previous "-vv" again. This means that "-vv -v" is
equivalent to a single -v. This avoids unwanted verbosity when
the option is mentioned in the command line and curl config
files.
Using it twice, e.g. "-vv", outputs time (--trace-time) and
transfer ids (--trace-ids), as well as enabling tracing for all
protocols (--trace-config protocol).
Adding a third verbose outputs transfer content (--trace-ascii
%) and enables tracing of more components (--trace-config
read,write,ssl).
A fourth time adds tracing of all network components.
(--trace-config network).
Any addition of the verbose option after that has no effect.
If you think this option does not give you the right details,
consider using --trace or --trace-ascii instead. Or use it only
once and use --trace-config to trace the specific components you
wish to see.
Note that verbose output of curl activities and network traffic
might contain sensitive data, including usernames, credentials
or secret data content. Be aware and be careful when sharing
trace logs with others.
When the output contains protocol headers, those lines might in-
clude carriage return (ASCII code 13) characters, even on plat-
forms that otherwise normally only use linefeed to signify line
separations - as curl shows the exact contents arriving from the
server.
This option is global and does not need to be specified for each
use of --next.
Providing --verbose multiple times has no extra effect. Disable
it again with --no-verbose.
Example:
curl --verbose https://example.com
This option is mutually exclusive with --trace and
--trace-ascii. See also -i, --show-headers, -s, --silent,
--trace and --trace-ascii.
-V, --version
Display information about curl and the libcurl version it uses.
The first line includes the full version of curl, libcurl and
other 3rd party libraries linked with the executable.
This line may contain one or more TLS libraries. curl can be
built to support more than one TLS library which then makes curl
- at start-up - select which particular backend to use for this
invocation.
If curl supports more than one TLS library like this, the ones
that are not selected by default are listed within parentheses.
Thus, if you do not specify which backend to use (with the
"CURL_SSL_BACKEND" environment variable) the one listed without
parentheses is used. Such builds also have "MultiSSL" set as a
feature.
The second line (starts with "Release-Date:") shows the release
date.
The third line (starts with "Protocols:") shows all protocols
that libcurl reports to support.
The fourth line (starts with "Features:") shows specific fea-
tures libcurl reports to offer. Available features include:
alt-svc
Support for the Alt-Svc: header is provided.
AsynchDNS
This curl uses asynchronous name resolves. Asynchronous
name resolves can be done using either the c-ares or the
threaded resolver backends.
brotli Support for automatic brotli compression over HTTP(S).
CharConv
curl was built with support for character set conversions
(like EBCDIC)
Debug This curl uses a libcurl built with Debug. This enables
more error-tracking and memory debugging etc. For
curl-developers only.
ECH ECH support is present.
gsasl The built-in SASL authentication includes extensions to
support SCRAM because libcurl was built with libgsasl.
GSS-API
GSS-API is supported.
HSTS HSTS support is present.
HTTP2 HTTP/2 support has been built-in.
HTTP3 HTTP/3 support has been built-in.
HTTPS-proxy
This curl is built to support HTTPS proxy.
IDN This curl supports IDN - international domain names.
IPv6 You can use IPv6 with this.
Kerberos
Kerberos V5 authentication is supported.
Largefile
This curl supports transfers of large files, files larger
than 2GB.
libz Automatic decompression (via gzip, deflate) of compressed
files over HTTP is supported.
MultiSSL
This curl supports multiple TLS backends.
NTLM NTLM authentication is supported.
NTLM_WB
NTLM delegation to winbind helper is supported. This
feature was removed from curl in 8.8.0.
PSL PSL is short for Public Suffix List and means that this
curl has been built with knowledge about "public suf-
fixes".
SPNEGO SPNEGO authentication is supported.
SSL SSL versions of various protocols are supported, such as
HTTPS, FTPS, POP3S and so on.
SSLS-EXPORT
This build supports TLS session export/import, like with
the --ssl-sessions.
SSPI SSPI is supported.
TLS-SRP
SRP (Secure Remote Password) authentication is supported
for TLS.
TrackMemory
Debug memory tracking is supported.
Unicode
Unicode support on Windows.
UnixSockets
Unix sockets support is provided.
zstd Automatic decompression (via zstd) of compressed files
over HTTP is supported.
Example:
curl --version
See also -h, --help and -M, --manual.
--vlan-priority <priority>
(All) Set VLAN priority as defined in IEEE 802.1Q.
This field is set on Ethernet level, and only works within a lo-
cal network.
The valid range for <priority> is 0 to 7.
If --vlan-priority is provided several times, the last set value
is used.
Example:
curl --vlan-priority 4 https://example.com
Added in 8.9.0. See also --ip-tos.
-w, --write-out <format>
Make curl display information on stdout after a completed trans-
fer. The format is a string that may contain plain text mixed
with any number of variables. The format can be specified as a
literal "string", or you can have curl read the format from a
file with "@filename" and to tell curl to read the format from
stdin you write "@-".
The variables present in the output format are substituted by
the value or text that curl thinks fit, as described below. All
variables are specified as %{variable_name} and to output a nor-
mal % you just write them as %%. You can output a newline by us-
ing \n, a carriage return with \r and a tab space with \t.
The output is by default written to standard output, but can be
changed with %{stderr} and %output{}.
Output HTTP header values from the transfer's most recent server
response by using %header{name} where name is the case insensi-
tive name of the header (without the trailing colon). The header
contents are exactly as delivered over the network but with
leading and trailing whitespace and newlines stripped off (added
in 7.84.0).
Select a specific target destination file to write the output
to, by using %output{name} (added in curl 8.3.0) where name is
the full filename. The output following that instruction is then
written to that file. More than one %output{} instruction can be
specified in the same write-out argument. If the filename cannot
be created, curl leaves the output destination to the one used
prior to the %output{} instruction. Use %output{>>name} to ap-
pend data to an existing file.
This output is done independently of if the file transfer was
successful or not.
If the specified action or output specified with this option
fails in any way, it does not make curl return a (different) er-
ror.
NOTE: On Windows, the %-symbol is a special symbol used to ex-
pand environment variables. In batch files, all occurrences of %
must be doubled when using this option to properly escape. If
this option is used at the command prompt then the % cannot be
escaped and unintended expansion is possible.
The variables available are:
certs Output the certificate chain with details. Supported only
by the OpenSSL, GnuTLS, Schannel, Rustls, and Secure
Transport backends. (Added in 7.88.0)
conn_id
The connection identifier last used by the transfer. The
connection id is unique number among all connections us-
ing the same connection cache. (Added in 8.2.0)
content_type
The Content-Type of the requested document, if there was
any.
errormsg
The error message. (Added in 7.75.0)
exitcode
The numerical exit code of the transfer. (Added in
7.75.0)
filename_effective
The ultimate filename that curl writes out to. This is
only meaningful if curl is told to write to a file with
the -O, --remote-name or -o, --output option. It is most
useful in combination with the -J, --remote-header-name
option.
ftp_entry_path
The initial path curl ended up in when logging on to the
remote FTP server.
header{name}
The value of header "name" from the transfer's most re-
cent server response. Unlike other variables, the vari-
able name "header" is not in braces. For example
"%header{date}". Refer to -w, --write-out remarks. (Added
in 7.84.0)
header_json
A JSON object with all HTTP response headers from the re-
cent transfer. Values are provided as arrays, since in
the case of multiple headers there can be multiple val-
ues. (Added in 7.83.0)
The header names provided in lowercase, listed in order
of appearance over the wire. Except for duplicated head-
ers. They are grouped on the first occurrence of that
header, each value is presented in the JSON array.
http_code
The numerical response code that was found in the last
retrieved HTTP(S) or FTP(s) transfer.
http_connect
The numerical code that was found in the last response
(from a proxy) to a curl CONNECT request.
http_version
The http version that was effectively used.
json A JSON object with all available keys. (Added in 7.70.0)
local_ip
The IP address of the local end of the most recently done
connection - can be either IPv4 or IPv6.
local_port
The local port number of the most recently done connec-
tion.
method The http method used in the most recent HTTP request.
(Added in 7.72.0)
num_certs
Number of server certificates received in the TLS hand-
shake. Supported only by the OpenSSL, GnuTLS, Schannel,
Rustls and Secure Transport backends. (Added in 7.88.0)
num_connects
Number of new connects made in the recent transfer.
num_headers
The number of response headers in the most recent request
(restarted at each redirect). Note that the status line
IS NOT a header. (Added in 7.73.0)
num_redirects
Number of redirects that were followed in the request.
num_retries
Number of retries actually performed when "--retry" has
been used. (Added in 8.9.0)
onerror
The rest of the output is only shown if the transfer re-
turned a non-zero error. (Added in 7.75.0)
output{filename}
From this point on, the -w, --write-out output is written
to the filename specified in braces. The filename can be
prefixed with ">>" to append to the file. Unlike other
variables, the variable name "output" is not in braces.
For example "%output{>>stats.txt}". Refer to -w,
--write-out remarks. (Added in 8.3.0)
proxy_ssl_verify_result
The result of the HTTPS proxy's SSL peer certificate ver-
ification that was requested. 0 means the verification
was successful.
proxy_used
Returns 1 if the previous transfer used a proxy, other-
wise 0. Useful to for example determine if a "NOPROXY"
pattern matched the hostname or not. (Added in 8.7.0)
redirect_url
When an HTTP request was made without -L, --location to
follow redirects (or when --max-redirs is met), this
variable shows the actual URL a redirect would have gone
to.
referer
The Referer: header, if there was any. (Added in 7.76.0)
remote_ip
The remote IP address of the most recently done connec-
tion - can be either IPv4 or IPv6.
remote_port
The remote port number of the most recently done connec-
tion.
response_code
The numerical response code that was found in the last
transfer (formerly known as "http_code").
scheme The URL scheme (sometimes called protocol) that was ef-
fectively used.
size_download
The total amount of bytes that were downloaded. This is
the size of the body/data that was transferred, excluding
headers.
size_header
The total amount of bytes of the downloaded headers.
size_request
The total amount of bytes that were sent in the HTTP re-
quest.
size_upload
The total amount of bytes that were uploaded. This is the
size of the body/data that was transferred, excluding
headers.
speed_download
The average download speed that curl measured for the
complete download. Bytes per second.
speed_upload
The average upload speed that curl measured for the com-
plete upload. Bytes per second.
ssl_verify_result
The result of the SSL peer certificate verification that
was requested. 0 means the verification was successful.
stderr From this point on, the -w, --write-out output is written
to standard error. (Added in 7.63.0)
stdout From this point on, the -w, --write-out output is written
to standard output. This is the default, but can be used
to switch back after switching to stderr. (Added in
7.63.0)
time_appconnect
The time, in seconds, it took from the start until the
SSL/SSH/etc connect/handshake to the remote host was com-
pleted.
time_connect
The time, in seconds, it took from the start until the
TCP connect to the remote host (or proxy) was completed.
time_namelookup
The time, in seconds, it took from the start until the
name resolving was completed.
time_posttransfer
The time it took from the start until the last byte is
sent by libcurl. In microseconds. (Added in 8.10.0)
time_pretransfer
The time, in seconds, it took from the start until the
file transfer was just about to begin. This includes all
pre-transfer commands and negotiations that are specific
to the particular protocol(s) involved.
time_queue
The time, in seconds, the transfer was queued during its
run. This adds the queue time for each redirect step that
may have happened. Transfers may be queued for signifi-
cant amounts of time when connection or parallel limits
are in place. (Added in 8.12.0)
time_redirect
The time, in seconds, it took for all redirection steps
including name lookup, connect, pretransfer and transfer
before the final transaction was started. "time_redirect"
shows the complete execution time for multiple redirec-
tions.
time_starttransfer
The time, in seconds, it took from the start until the
first byte was received. This includes time_pretransfer
and also the time the server needed to calculate the re-
sult.
time_total
The total time, in seconds, that the full operation
lasted.
tls_earlydata
The amount of bytes that were sent as TLSv1.3 early data.
This is 0 if this TLS feature was not used and negative
if the data sent had been rejected by the server. The use
of early data is enabled via the command line option
"--tls-earlydata". (Added in 8.12.0)
url The URL that was fetched. (Added in 7.75.0)
url.scheme
The scheme part of the URL that was fetched. (Added in
8.1.0)
url.user
The user part of the URL that was fetched. (Added in
8.1.0)
url.password
The password part of the URL that was fetched. (Added in
8.1.0)
url.options
The options part of the URL that was fetched. (Added in
8.1.0)
url.host
The host part of the URL that was fetched. (Added in
8.1.0)
url.port
The port number of the URL that was fetched. If no port
number was specified and the URL scheme is known, that
scheme's default port number is shown. (Added in 8.1.0)
url.path
The path part of the URL that was fetched. (Added in
8.1.0)
url.query
The query part of the URL that was fetched. (Added in
8.1.0)
url.fragment
The fragment part of the URL that was fetched. (Added in
8.1.0)
url.zoneid
The zone id part of the URL that was fetched. (Added in
8.1.0)
urle.scheme
The scheme part of the effective (last) URL that was
fetched. (Added in 8.1.0)
urle.user
The user part of the effective (last) URL that was
fetched. (Added in 8.1.0)
urle.password
The password part of the effective (last) URL that was
fetched. (Added in 8.1.0)
urle.options
The options part of the effective (last) URL that was
fetched. (Added in 8.1.0)
urle.host
The host part of the effective (last) URL that was
fetched. (Added in 8.1.0)
urle.port
The port number of the effective (last) URL that was
fetched. If no port number was specified, but the URL
scheme is known, that scheme's default port number is
shown. (Added in 8.1.0)
urle.path
The path part of the effective (last) URL that was
fetched. (Added in 8.1.0)
urle.query
The query part of the effective (last) URL that was
fetched. (Added in 8.1.0)
urle.fragment
The fragment part of the effective (last) URL that was
fetched. (Added in 8.1.0)
urle.zoneid
The zone id part of the effective (last) URL that was
fetched. (Added in 8.1.0)
urlnum The URL index number of this transfer, 0-indexed. Un-
globbed URLs share the same index number as the origin
globbed URL. (Added in 7.75.0)
url_effective
The URL that was fetched last. This is most meaningful if
you have told curl to follow location: headers.
xfer_id
The numerical identifier of the last transfer done. -1 if
no transfer has been started yet for the handle. The
transfer id is unique among all transfers performed using
the same connection cache. (Added in 8.2.0)
If --write-out is provided several times, the last set value is
used.
Example:
curl -w '%{response_code}\n' https://example.com
See also -v, --verbose and -I, --head.
--xattr
Store metadata in the extended file attributes.
When saving output to a file, tell curl to store file metadata
in extended file attributes. Currently, "curl" is stored in the
"creator" attribute, the URL is stored in the "xdg.origin.url"
attribute and, for HTTP, the content type is stored in the
"mime_type" attribute. If the file system does not support ex-
tended attributes, a warning is issued.
Providing --xattr multiple times has no extra effect. Disable
it again with --no-xattr.
Example:
curl --xattr -o storage https://example.com
See also -R, --remote-time, -w, --write-out and -v, --verbose.
FILES
~/.curlrc
Default config file, see -K, --config for details.
ENVIRONMENT
The environment variables can be specified in lower case or upper case.
The lower case version has precedence. "http_proxy" is an exception as
it is only available in lower case.
Using an environment variable to set the proxy has the same effect as
using the -x, --proxy option.
http_proxy [protocol://]<host>[:port]
Sets the proxy server to use for HTTP.
HTTPS_PROXY [protocol://]<host>[:port]
Sets the proxy server to use for HTTPS.
[url-protocol]_PROXY [protocol://]<host>[:port]
Sets the proxy server to use for [url-protocol], where the pro-
tocol is a protocol that curl supports and as specified in a
URL. FTP, FTPS, POP3, IMAP, SMTP, LDAP, etc.
ALL_PROXY [protocol://]<host>[:port]
Sets the proxy server to use if no protocol-specific proxy is
set.
NO_PROXY <comma-separated list of hosts/domains>
list of hostnames that should not go through any proxy. If set
to an asterisk '*' only, it matches all hosts. Each name in this
list is matched as either a domain name which contains the host-
name, or the hostname itself.
This environment variable disables use of the proxy even when
specified with the -x, --proxy option. That is
NO_PROXY=direct.example.com curl -x http://proxy.example.com
http://direct.example.com
accesses the target URL directly, and
NO_PROXY=direct.example.com curl -x http://proxy.example.com
http://somewhere.example.com
accesses the target URL through the proxy.
The list of hostnames can also include numerical IP addresses,
and IPv6 versions should then be given without enclosing brack-
ets.
IP addresses can be specified using CIDR notation: an appended
slash and number specifies the number of "network bits" out of
the address to use in the comparison (added in 7.86.0). For ex-
ample "192.168.0.0/16" would match all addresses starting with
"192.168".
APPDATA <dir>
On Windows, this variable is used when trying to find the home
directory. If the primary home variables are all unset.
COLUMNS <terminal width>
If set, the specified number of characters is used as the termi-
nal width when the alternative progress-bar is shown. If not
set, curl tries to figure it out using other ways.
CURL_CA_BUNDLE <file>
If set, it is used as the --cacert value. This environment vari-
able is ignored if Schannel is used as the TLS backend.
CURL_HOME <dir>
If set, is the first variable curl checks when trying to find
its home directory. If not set, it continues to check XDG_CON-
FIG_HOME
CURL_SSL_BACKEND <TLS backend>
If curl was built with support for "MultiSSL", meaning that it
has built-in support for more than one TLS backend, this envi-
ronment variable can be set to the case insensitive name of the
particular backend to use when curl is invoked. Setting a name
that is not a built-in alternative makes curl stay with the de-
fault.
SSL backend names (case-insensitive): bearssl, gnutls, mbedtls,
openssl, rustls, schannel, secure-transport, wolfssl
HOME <dir>
If set, this is used to find the home directory when that is
needed. Like when looking for the default .curlrc. CURL_HOME and
XDG_CONFIG_HOME have preference.
QLOGDIR <directory name>
If curl was built with HTTP/3 support, setting this environment
variable to a local directory makes curl produce qlogs in that
directory, using file names named after the destination connec-
tion id (in hex). Do note that these files can become rather
large. Works with the ngtcp2 and quiche QUIC backends.
SHELL Used on VMS when trying to detect if using a DCL or a Unix
shell.
SSL_CERT_DIR <dir>
If set, it is used as the --capath value. This environment vari-
able is ignored if Schannel is used as the TLS backend.
SSL_CERT_FILE <path>
If set, it is used as the --cacert value. This environment vari-
able is ignored if Schannel is used as the TLS backend.
SSLKEYLOGFILE <filename>
If you set this environment variable to a filename, curl stores
TLS secrets from its connections in that file when invoked to
enable you to analyze the TLS traffic in real time using network
analyzing tools such as Wireshark. This works with the following
TLS backends: OpenSSL, LibreSSL (TLS 1.2 max), BoringSSL,
GnuTLS, wolfSSL and Rustls.
USERPROFILE <dir>
On Windows, this variable is used when trying to find the home
directory. If the other, primary, variables are all unset. If
set, curl uses the path "$USERPROFILE\Application Data".
XDG_CONFIG_HOME <dir>
If CURL_HOME is not set, this variable is checked when looking
for a default .curlrc file.
PROXY PROTOCOL PREFIXES
The proxy string may be specified with a protocol:// prefix to specify
alternative proxy protocols.
If no protocol is specified in the proxy string or if the string does
not match a supported one, the proxy is treated as an HTTP proxy.
The supported proxy protocol prefixes are as follows:
http://
Makes it use it as an HTTP proxy. The default if no scheme pre-
fix is used.
https://
Makes it treated as an HTTPS proxy.
socks4://
Makes it the equivalent of --socks4
socks4a://
Makes it the equivalent of --socks4a
socks5://
Makes it the equivalent of --socks5
socks5h://
Makes it the equivalent of --socks5-hostname
EXIT CODES
There are a bunch of different error codes and their corresponding er-
ror messages that may appear under error conditions. At the time of
this writing, the exit codes are:
0 Success. The operation completed successfully according to the
instructions.
1 Unsupported protocol. This build of curl has no support for this
protocol.
2 Failed to initialize.
3 URL malformed. The syntax was not correct.
4 A feature or option that was needed to perform the desired re-
quest was not enabled or was explicitly disabled at build-time.
To make curl able to do this, you probably need another build of
libcurl.
5 Could not resolve proxy. The given proxy host could not be re-
solved.
6 Could not resolve host. The given remote host could not be re-
solved.
7 Failed to connect to host.
8 Weird server reply. The server sent data curl could not parse.
9 FTP access denied. The server denied login or denied access to
the particular resource or directory you wanted to reach. Most
often you tried to change to a directory that does not exist on
the server.
10 FTP accept failed. While waiting for the server to connect back
when an active FTP session is used, an error code was sent over
the control connection or similar.
11 FTP weird PASS reply. curl could not parse the reply sent to the
PASS request.
12 During an active FTP session while waiting for the server to
connect back to curl, the timeout expired.
13 FTP weird PASV reply, curl could not parse the reply sent to the
PASV request.
14 FTP weird 227 format. curl could not parse the 227-line the
server sent.
15 FTP cannot use host. Could not resolve the host IP we got in the
227-line.
16 HTTP/2 error. A problem was detected in the HTTP2 framing layer.
This is somewhat generic and can be one out of several problems,
see the error message for details.
17 FTP could not set binary. Could not change transfer method to
binary.
18 Partial file. Only a part of the file was transferred.
19 FTP could not download/access the given file, the RETR (or simi-
lar) command failed.
21 FTP quote error. A quote command returned error from the server.
22 HTTP page not retrieved. The requested URL was not found or re-
turned another error with the HTTP error code being 400 or
above. This return code only appears if -f, --fail is used.
23 Write error. curl could not write data to a local filesystem or
similar.
25 Failed starting the upload. For FTP, the server typically denied
the STOR command.
26 Read error. Various reading problems.
27 Out of memory. A memory allocation request failed.
28 Operation timeout. The specified time-out period was reached ac-
cording to the conditions.
30 FTP PORT failed. The PORT command failed. Not all FTP servers
support the PORT command, try doing a transfer using PASV in-
stead.
31 FTP could not use REST. The REST command failed. This command is
used for resumed FTP transfers.
33 HTTP range error. The range "command" did not work.
34 HTTP post error. Internal post-request generation error.
35 SSL connect error. The SSL handshaking failed.
36 Bad download resume. Could not continue an earlier aborted down-
load.
37 FILE could not read file. Failed to open the file. Permissions?
38 LDAP cannot bind. LDAP bind operation failed.
39 LDAP search failed.
41 Function not found. A required LDAP function was not found.
42 Aborted by callback. An application told curl to abort the oper-
ation.
43 Internal error. A function was called with a bad parameter.
45 Interface error. A specified outgoing interface could not be
used.
47 Too many redirects. When following redirects, curl hit the maxi-
mum amount.
48 Unknown option specified to libcurl. This indicates that you
passed a weird option to curl that was passed on to libcurl and
rejected. Read up in the manual.
49 Malformed telnet option.
52 The server did not reply anything, which here is considered an
error.
53 SSL crypto engine not found.
54 Cannot set SSL crypto engine as default.
55 Failed sending network data.
56 Failure in receiving network data.
58 Problem with the local certificate.
59 Could not use specified SSL cipher.
60 Peer certificate cannot be authenticated with known CA certifi-
cates.
61 Unrecognized transfer encoding.
63 Maximum file size exceeded.
64 Requested FTP SSL level failed.
65 Sending the data requires a rewind that failed.
66 Failed to initialize SSL Engine.
67 The username, password, or similar was not accepted and curl
failed to log in.
68 File not found on TFTP server.
69 Permission problem on TFTP server.
70 Out of disk space on TFTP server.
71 Illegal TFTP operation.
72 Unknown TFTP transfer ID.
73 File already exists (TFTP).
74 No such user (TFTP).
77 Problem reading the SSL CA cert (path? access rights?).
78 The resource referenced in the URL does not exist.
79 An unspecified error occurred during the SSH session.
80 Failed to shut down the SSL connection.
82 Could not load CRL file, missing or wrong format.
83 Issuer check failed.
84 The FTP PRET command failed.
85 Mismatch of RTSP CSeq numbers.
86 Mismatch of RTSP Session Identifiers.
87 Unable to parse FTP file list.
88 FTP chunk callback reported error.
89 No connection available, the session is queued.
90 SSL public key does not match pinned public key.
91 Invalid SSL certificate status.
92 Stream error in HTTP/2 framing layer.
93 An API function was called from inside a callback.
94 An authentication function returned an error.
95 A problem was detected in the HTTP/3 layer. This is somewhat
generic and can be one out of several problems, see the error
message for details.
96 QUIC connection error. This error may be caused by an SSL li-
brary error. QUIC is the protocol used for HTTP/3 transfers.
97 Proxy handshake error.
98 A client-side certificate is required to complete the TLS hand-
shake.
99 Poll or select returned fatal error.
100 A value or data field grew larger than allowed.
XX More error codes might appear here in future releases. The ex-
isting ones are meant to never change.
BUGS
If you experience any problems with curl, submit an issue in the
project's bug tracker on GitHub: https://github.com/curl/curl/issues
AUTHORS
Daniel Stenberg is the main author, but the whole list of contributors
is found in the separate THANKS file.
WWW
https://curl.se
SEE ALSO
ftp(1), wget(1)
curl 8.14.1 2025-09-10 curl(1)
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