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NAME curl - transfer a URL
SYNOPSIS curl [options] [URL...]
DESCRIPTION curl is a tool to transfer data from or to a server, using one of the supported protocols (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET and TFTP). The command is designed to work without user interaction.
curl offers a busload of useful tricks like proxy support, user authen-
tication, FTP upload, HTTP post, SSL connections, cookies, file trans-
fer resume, Metalink, and more. As you will see below, the number of
features will make your head spin!
curl is powered by libcurl for all transfer-related features. See
libcurl(3) for details.
URL The URL syntax is protocol-dependent. You'll find a detailed descrip- tion in RFC 3986.
You can specify multiple URLs or parts of URLs by writing part sets
within braces as in:
http://site.{one,two,three}.com
or you can get sequences of alphanumeric series by using [] as in:
ftp://ftp.example.com/file[1-100].txt
ftp://ftp.example.com/file[001-100].txt (with leading zeros)
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 any amount of URLs on the command line. They will be
fetched in a sequential manner in the specified order.
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 '*'.
Provide the IPv6 zone index in the URL with an escaped percentage sign
and the interface name. Like in
http://[fe80::3%25eth0]/
If you specify URL without protocol:// prefix, curl will attempt to
guess what protocol you might want. It will then default to HTTP but
try other protocols based on often-used host name prefixes. For exam-
ple, for host names starting with "ftp." curl will assume you want to
speak FTP.
curl will do its best to use what you pass to it as a URL. It is not
trying to validate it as a syntactically correct URL by any means but
is instead very liberal with what it accepts.
curl will attempt to re-use connections for multiple file transfers, so
that getting many files from the same server will not do multiple con-
nects / handshakes. This improves speed. Of course this is only done on
files specified on a single command line and cannot be used between
separate curl invokes.
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 number of bytes and the speeds are 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.
It is not the same case for 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.
OPTIONS Options start with one or two dashes. Many of the options require an additional value next to them.
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 don't 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 exact same option name
but prefix it with "no-". However, in this list we mostly only list and
show the --option version of them. (This concept with --no options was
added in 7.19.0. Previously most options were toggled on/off on
repeated use of the same command line option.)
--abstract-unix-socket <path>
(HTTP) Connect through an abstract Unix domain socket, instead
of using the network. Note: netstat shows the path of an
abstract socket prefixed with '@', however the <path> argument
should not have this leading character.
Added in 7.53.0.
--anyauth
(HTTP) Tells curl to figure out authentication method by itself,
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 is used instead of setting a specific authentication
method, which you can do with --basic, --digest, --ntlm, and
--negotiate.
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 will fail.
Used together with -u, --user.
See also --proxy-anyauth and --basic and --digest.
-a, --append
(FTP SFTP) When used in an upload, this makes curl append to the
target file instead of overwriting it. If the remote file
doesn't exist, it will be created. Note that this flag is
ignored by some SFTP servers (including OpenSSH).
--basic
(HTTP) Tells curl to use HTTP Basic authentication with the
remote host. This is the default and this option is usually
pointless, unless 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.
See also --proxy-basic.
--cacert <CA certificate>
(TLS) Tells curl to 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 uses the given path as a path to a CA cert
bundle. This option overrides that variable.
The windows version of curl will automatically look for a CA
certs file named 'curl-ca-bundle.crt', either in the same direc-
tory as curl.exe, or in the Current Working Directory, or in any
folder along your PATH.
If curl is built against the NSS SSL library, the NSS PEM
PKCS#11 module (libnsspem.so) needs to be available for this
option to work properly.
(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 will use the certificates in the system and
user Keychain to verify the peer, which is the preferred method
of verifying the peer's certificate chain.
If this option is used several times, the last one will be used.
--capath <dir>
(TLS) Tells curl to use the specified certificate directory to
verify the peer. Multiple paths can be provided by separating
them with ":" (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 --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 will be ignored,
and if it is used several times, the last one will be used.
--cert-status
(TLS) Tells curl to 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 is currently only implemented in the OpenSSL, GnuTLS and
NSS backends.
Added in 7.41.0.
--cert-type <type>
(TLS) Tells curl what certificate type the provided certificate
is in. PEM, DER and ENG are recognized types. If not specified,
PEM is assumed.
If this option is used several times, the last one will be used.
See also -E, --cert and --key and --key-type.
-E, --cert <certificate[:password]>
(TLS) Tells curl to use the specified client certificate file
when getting a file with HTTPS, FTPS or another SSL-based proto-
col. The certificate must be in PKCS#12 format if using Secure
Transport, or PEM format if using any other engine. If the
optional password isn't specified, it will be 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.
If curl is built against the NSS SSL library then this option
can tell curl the nickname of the certificate to use within the
NSS database defined by the environment variable SSL_DIR (or by
default /etc/pki/nssdb). If the NSS PEM PKCS#11 module (lib-
nsspem.so) is available then PEM files may be loaded. If you
want to use a file from the current directory, please precede it
with "./" prefix, in order to avoid confusion with a nickname.
If the nickname contains ":", it needs to be preceded by "\" so
that it is not recognized as password delimiter. If the nick-
name contains "\", it needs to be escaped as "\\" so that it is
not recognized as an escape character.
(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.
If this option is used several times, the last one will be used.
See also --cert-type and --key and --key-type.
--ciphers <list of ciphers>
(TLS) Specifies which ciphers to use in the connection. The list
of ciphers must specify valid ciphers. Read up on SSL cipher
list details on this URL:
https://curl.haxx.se/docs/ssl-ciphers.html
If this option is used several times, the last one will be used.
--compressed
(HTTP) Request a compressed response using one of the algorithms
curl supports, and save the uncompressed document. If this
option is used and the server sends an unsupported encoding,
curl will report an error.
-K, --config <file>
Specify which config file to read curl arguments from. The con-
fig file is a text file in which command line arguments can be
written which then will be used as if they were written on the
actual command line.
Options and their parameters must be specified on the same con-
fig file line, 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 character between the option and its parameter.
If the parameter is to contain whitespace, the parameter must be
enclosed within quotes. 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
column of a config line is a '#' character, the rest of the line
will be treated as a comment. Only write one option per physical
line in the config file.
Specify the filename to -K, --config as '-' 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.haxx.se/docs/"
When curl is invoked, it always (unless -q, --disable is used)
checks for a default config file and uses it if found. The
default config file is checked for in the following places in
this order:
1) curl tries to find the "home dir": It first checks for the
CURL_HOME and then the HOME environment variables. Failing that,
it uses getpwuid() on Unix-like systems (which returns the home
dir given the current user in your system). On Windows, it then
checks for the APPDATA variable, or as a last resort the '%USER-
PROFILE%\Application Data'.
2) On windows, if there is no _curlrc file in the home dir, it
checks for one in the same dir the curl executable is placed. On
Unix-like systems, it will simply try to load .curlrc from the
determined home dir.
# --- 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 ---
This option can be used multiple times to load multiple config
files.
--connect-timeout <seconds>
Maximum time in seconds that you allow curl's connection to
take. This only limits the connection phase, so if curl con-
nects within the given period it will continue - if not it will
exit. Since version 7.32.0, this option accepts decimal values.
If this option is used several times, the last one will be used.
See also -m, --max-time.
--connect-to <HOST1:PORT1:HOST2:PORT2>
For a request to the given HOST:PORT pair, connect to CONNECT-
TO-HOST:CONNECT-TO-PORT instead. This option is suitable to
direct requests at a specific server, e.g. at a specific cluster
node in a cluster of servers. This option is only used to
establish the network connection. It does NOT affect the host-
name/port that is used for TLS/SSL (e.g. SNI, certificate veri-
fication) or for the application protocols. "host" and "port"
may be the empty string, meaning "any host/port". "connect-to-
host" and "connect-to-port" may also be the empty string, mean-
ing "use the request's original host/port".
This option can be used many times to add many connect rules.
See also --resolve and -H, --header. Added in 7.49.0.
-C, --continue-at <offset>
Continue/Resume a previous file transfer at the given offset.
The given offset is the exact number of bytes that will be
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 will not be used by curl.
Use "-C -" to tell curl to automatically find out where/how to
resume the transfer. It then uses the given output/input files
to figure that out.
If this option is used several times, the last one will be used.
See also -r, --range.
-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. If no cookies are known, no data will be written. The
file will be written using the Netscape cookie file format. If
you set the file name to a single dash, "-", the cookies will be
written to stdout.
This command line option will activate the cookie engine that
makes curl record and use cookies. Another way to activate it is
to use the -b, --cookie option.
If the cookie jar can't be created or written to, the whole curl
operation won't fail or even report an error clearly. Using -v,
--verbose will get a warning displayed, but that is the only
visible feedback you get about this possibly lethal situation.
If this option is used several times, the last specified file
name will be used.
-b, --cookie <data>
(HTTP) Pass the data to the HTTP server in the Cookie header. It
is supposedly the data previously received from the server in a
"Set-Cookie:" line. The data should be in the format
"NAME1=VALUE1; NAME2=VALUE2".
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 will make curl record
incoming cookies, which may be handy if you're using this in
combination with the -L, --location option or do multiple URL
transfers on the same invoke.
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 will be written to the file. To store cookies, use the
-c, --cookie-jar option.
Exercise caution if you are using this option and multiple
transfers may occur. If you use the NAME1=VALUE1; format, or in
a file use the Set-Cookie format and don't specify a domain,
then the cookie is sent for any domain (even after redirects are
followed) and cannot be modified by a server-set cookie. If the
cookie engine is enabled and a server sets a cookie of the same
name then both will be sent on a future transfer to that server,
likely not what you intended. To address these issues set a
domain in Set-Cookie (doing that will include sub domains) or
use the Netscape format.
If this option is used several times, the last one will be used.
Users very often want to both read cookies from a file and write
updated cookies back to a file, so using both -b, --cookie and
-c, --cookie-jar in the same command line is common.
--create-dirs
When used in conjunction with the -o, --output option, curl will
create the necessary local directory hierarchy as needed. This
option creates the dirs mentioned with the -o, --output option,
nothing else. If the --output file name uses no dir or if the
dirs it mentions already exist, no dir will be created.
To create remote directories when using FTP or SFTP, try --ftp-
create-dirs.
--crlf (FTP SMTP) Convert LF to CRLF in upload. Useful for MVS
(OS/390).
(SMTP added in 7.40.0)
--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 this option is used several times, the last one will be used.
Added in 7.19.7.
--data-ascii <data>
(HTTP) This is just an alias for -d, --data.
--data-binary <data>
(HTTP) This posts data exactly as specified with no extra pro-
cessing whatsoever.
If you start the data with the letter @, the rest should be a
filename. Data is posted in a similar manner as -d, --data
does, except that newlines and carriage returns are preserved
and conversions are never done.
If this option is used several times, the ones following the
first will append data as described in -d, --data.
--data-raw <data>
(HTTP) This posts data similarly to -d, --data but without the
special interpretation of the @ character.
See also -d, --data. Added in 7.43.0.
--data-urlencode <data>
(HTTP) This posts 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
This will make curl URL-encode the content and pass that
on. Just be careful so that the content doesn't contain
any = or @ symbols, as that will then make the syntax
match one of the other cases below!
=content
This will make curl URL-encode the content and pass that
on. The preceding = symbol is not included in the data.
name=content
This will make curl URL-encode the content part and pass
that on. Note that the name part is expected to be URL-
encoded already.
@filename
This will make curl load data from the given file
(including any newlines), URL-encode that data and pass
it on in the POST.
name@filename
This will make curl 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=urlencoded-file-content. Note
that the name is expected to be URL-encoded already.
See also -d, --data and --data-raw. Added in 7.18.0.
-d, --data <data>
(HTTP) Sends 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 will
cause curl to pass the data to the server using the content-type
application/x-www-form-urlencoded. Compare 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 will be merged together
with a separating &-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
file name to read the data from, or - if you want curl to read
the data from stdin. Multiple files can also be specified. Post-
ing data from a file named from a file like that, carriage
returns and newlines will be stripped out. If you don't want the
@ character to have a special interpretation use --data-raw
instead.
See also --data-binary and --data-urlencode and --data-raw. This
option overrides -F, --form and -I, --head and --upload.
--delegation <LEVEL>
(GSS/kerberos) Set LEVEL to tell the server what it is allowed
to delegate when it comes to user credentials.
none Don't 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.
--digest
(HTTP) Enables HTTP Digest authentication. This is an authenti-
cation scheme that prevents the password from being sent over
the wire in clear text. Use this in combination with the normal
-u, --user option to set user name and password.
If this option is used several times, only the first one is
used.
See also -u, --user and --proxy-digest and --anyauth. This
option overrides --basic and --ntlm and --negotiate.
--disable-eprt
(FTP) Tell curl to disable the use of the EPRT and LPRT commands
when doing active FTP transfers. Curl will normally always first
attempt to use EPRT, then LPRT before using PORT, but with this
option, it will use PORT right away. EPRT and LPRT are exten-
sions to the original FTP protocol, and may not work on all
servers, but they enable 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 will have 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.
--disable-epsv
(FTP) (FTP) Tell curl to disable the use of the EPSV command
when doing passive FTP transfers. Curl will normally always
first attempt to use EPSV before PASV, but with this option, it
will not try using 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 will have 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.
-q, --disable
If used as the first parameter on the command line, the curlrc
config file will not be read and used. See the -K, --config for
details on the default config file search path.
--dns-interface <interface>
(DNS) Tell curl to send outgoing DNS requests through <inter-
face>. This option is a counterpart to --interface (which does
not affect DNS). The supplied string must be an interface name
(not an address).
See also --dns-ipv4-addr and --dns-ipv6-addr. --dns-interface
requires that the underlying libcurl was built to support c-
ares. Added in 7.33.0.
--dns-ipv4-addr <address>
(DNS) Tell curl to bind to <ip-address> when making IPv4 DNS
requests, so that the DNS requests originate from this address.
The argument should be a single IPv4 address.
See also --dns-interface and --dns-ipv6-addr. --dns-ipv4-addr
requires that the underlying libcurl was built to support c-
ares. Added in 7.33.0.
--dns-ipv6-addr <address>
(DNS) Tell curl to bind to <ip-address> when making IPv6 DNS
requests, so that the DNS requests originate from this address.
The argument should be a single IPv6 address.
See also --dns-interface and --dns-ipv4-addr. --dns-ipv6-addr
requires that the underlying libcurl was built to support c-
ares. Added in 7.33.0.
--dns-servers <addresses>
Set the list of DNS servers to be used instead of the system
default. The list of IP addresses should be separated with com-
mas. Port numbers may also optionally be given as :<port-number>
after each IP address.
--dns-servers requires that the underlying libcurl was built to
support c-ares. Added in 7.33.0.
-D, --dump-header <filename>
(HTTP FTP) Write the received protocol headers to the specified
file.
This option is handy to use when you want to store the headers
that an HTTP site sends to you. Cookies from the headers could
then be read in a second curl invocation by using the -b,
--cookie option! The -c, --cookie-jar option is a better way to
store cookies.
When used in FTP, the FTP server response lines are considered
being "headers" and thus are saved there.
If this option is used several times, the last one will be used.
See also -o, --output.
--egd-file <file>
(TLS) Specify the path name to the Entropy Gathering Daemon
socket. The socket is used to seed the random engine for SSL
connections.
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 (or none) of the engines may be
available at run-time.
--environment
Sets a range of environment variables, using the names the -w,
--write-out option supports, to allow easier extraction of use-
ful information after having run curl.
--environment requires that the underlying libcurl was built to
support RISC OS.
--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 will wait one second.
This option accepts decimal values! When curl stops waiting, it
will continue as if the response has been received.
See also --connect-timeout. Added in 7.47.0.
--fail-early
Fail and exit on the first detected transfer error.
When curl is used to do multiple transfers on the command line,
it will attempt to operate on each given URL, one by one. By
default, it will ignore errors if there are more URLs given and
the last URL's success will determine the error code curl
returns. So early failures will be "hidden" by subsequent suc-
cessful transfers.
Using this option, curl will instead return 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 fail-
ures go undetected by scripts and similar.
This option is global and does not need to be specified for each
use of -:, --next.
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.
Added in 7.52.0.
-f, --fail
(HTTP) Fail silently (no output at all) on server errors. This
is mostly done to better enable scripts etc to better deal with
failed attempts. 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 flag will pre-
vent curl from outputting that and return error 22.
This method is not fail-safe and there are occasions where non-
successful response codes will slip through, especially when
authentication is involved (response codes 401 and 407).
--false-start
(TLS) Tells curl to use false start during the TLS handshake.
False start is a mode where a TLS client will start sending
application data before verifying the server's Finished message,
thus saving a round trip when performing a full handshake.
This is currently only implemented in the NSS and Secure Trans-
port (on iOS 7.0 or later, or OS X 10.9 or later) backends.
Added in 7.42.0.
--form-string <name=string>
(HTTP) Similar to -F, --form except that the value string for
the named parameter is used literally. Leading '@' and '<' char-
acters, and the ';type=' string in the value have no special
meaning. Use this in preference to -F, --form if there's any
possibility that the string value may accidentally trigger the
'@' or '<' features of -F, --form.
See also -F, --form.
-F, --form <name=content>
(HTTP) This lets curl emulate a filled-in form in which a user
has pressed the submit button. This causes curl to POST data
using the Content-Type multipart/form-data according to RFC
2388. This enables uploading of binary files etc. To force the
'content' part to be a file, prefix the file name with an @
sign. To just get the content part from a file, prefix the file
name 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 get the contents for
that text field from a file.
Example: to send an image to a server, where 'profile' is the
name of the form-field to which portrait.jpg will be the input:
curl -F profile=@portrait.jpg https://example.com/upload.cgi
To read content from stdin instead of a file, use - as the file-
name. This goes for both @ and < constructs. Unfortunately it
does not support reading the file from a named pipe or similar,
as it needs the full size before the transfer starts.
You can also tell 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=@\"localfile\";filename=\"nameinpost\"" exam-
ple.com
or
curl -F 'file=@"localfile";filename="nameinpost"' 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.
See further examples and details in the MANUAL.
This option can be used multiple times.
This option overrides -d, --data and -I, --head and --upload.
--ftp-account <data>
(FTP) When an FTP server asks for "account data" after user name
and password has been provided, this data is sent off using the
ACCT command.
If this option is used several times, the last one will be used.
Added in 7.13.0.
--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" will tell the server to retrieve the username from
the certificate.
Added in 7.15.5.
--ftp-create-dirs
(FTP SFTP) When an FTP or SFTP URL/operation uses a path that
doesn't currently exist on the server, the standard behavior of
curl is to fail. Using this option, curl will instead attempt to
create missing directories.
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
curl does a single CWD operation for each path part in
the given URL. For deep hierarchies this means very many
commands. This is how RFC 1738 says it should be done.
This is the default but the slowest behavior.
nocwd curl does no CWD at all. curl will do SIZE, RETR, STOR
etc and give a full path to the server for all these com-
mands. This is the fastest behavior.
singlecwd
curl does one CWD with the full target directory and then
operates on the file "normally" (like in the multicwd
case). This is somewhat more standards compliant than
'nocwd' but without the full penalty of 'multicwd'.
Added in 7.15.1.
--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.
If this option is used several times, only the first one is
used. Undoing an enforced passive really isn't doable but you
must then instead enforce the correct -P, --ftp-port again.
Passive mode means that curl will try the EPSV command first and
then PASV, unless --disable-epsv is used.
See also --disable-epsv. Added in 7.11.0.
-P, --ftp-port <address>
(FTP) Reverses the default initiator/listener roles when con-
necting with FTP. This option makes curl use active mode. curl
then tells 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
i.e "eth0" to specify which interface's IP address you
want to use (Unix only)
IP address
i.e "192.168.10.1" to specify the exact IP address
host name
i.e "my.host.domain" to specify the machine
- make curl pick the same IP address that is already used
for the control connection
If this option is used several times, the last one will be used. Dis-
able 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++.
Since 7.19.5, you can append ":[start]-[end]" to the right of the
address, to tell curl what TCP port range to use. That means you spec-
ify 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.
See also --ftp-pasv and --disable-eprt.
--ftp-pret
(FTP) Tell curl to 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.
Added in 7.20.0.
--ftp-skip-pasv-ip
(FTP) Tell curl to not use the IP address the server suggests in
its response to curl's PASV command when curl connects the data
connection. Instead curl will re-use the same IP address it
already uses for the control connection.
This option has no effect if PORT, EPRT or EPSV is used instead
of PASV.
See also --ftp-pasv. Added in 7.14.2.
--ftp-ssl-ccc-mode <active/passive>
(FTP) Sets the CCC mode. The passive mode will not initiate the
shutdown, but instead wait for the server to do it, and will not
reply to the shutdown from the server. The active mode initiates
the shutdown and waits for a reply from the server.
See also --ftp-ssl-ccc. Added in 7.16.2.
--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 will be unencrypted. This allows NAT routers to fol-
low the FTP transaction. The default mode is passive.
See also --ssl and --ftp-ssl-ccc-mode. Added in 7.16.1.
--ftp-ssl-control
(FTP) Require SSL/TLS for the FTP login, clear for transfer.
Allows secure authentication, but non-encrypted data transfers
for efficiency. Fails the transfer if the server doesn't sup-
port SSL/TLS.
Added in 7.16.0.
-G, --get
When used, this option will make 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. The data will be appended to the URL with a '?' separator.
If used in combination with -I, --head, the POST data will
instead be appended to the URL with a HEAD request.
If this option is used several times, only the first one is
used. This is because undoing a GET doesn't make sense, but you
should then instead enforce the alternative method you prefer.
-g, --globoff
This option switches off the "URL globbing parser". When you set
this option, you can specify URLs that contain the letters {}[]
without having them being interpreted by curl itself. Note that
these letters are not normal legal URL contents but they should
be encoded according to the URI standard.
-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 file, curl displays the
file size and last modification time only.
-H, --header <header>
(HTTP) Extra header to include in the request when sending HTTP
to a server. 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 will be used instead of the internal one. This allows you
to make even trickier stuff than curl would normally do. You
should not replace internally set headers without knowing per-
fectly well what you're doing. Remove an internal header by giv-
ing 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-Custom-Header;" to send "X-Custom-Header:".
curl will make 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
returns, they will only mess things up for you.
See also the -A, --user-agent and -e, --referer options.
Starting in 7.37.0, you need --proxy-header to send custom head-
ers intended for a proxy.
Example:
curl -H "X-First-Name: Joe" http://example.com/
WARNING: headers set with this option will be set in all
requests - 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.
This option can be used multiple times to add/replace/remove
multiple headers.
-h, --help
Usage help. This lists all current command line options with a
short description.
--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 will refuse the connection with the host unless
the md5sums match.
Added in 7.17.1.
-0, --http1.0
(HTTP) Tells curl to use HTTP version 1.0 instead of using its
internally preferred HTTP version.
This option overrides --http1.1 and --http2.
--http1.1
(HTTP) Tells curl to use HTTP version 1.1.
This option overrides -0, --http1.0 and --http2. Added in
7.33.0.
--http2-prior-knowledge
(HTTP) Tells curl to issue its non-TLS HTTP requests using
HTTP/2 without HTTP/1.1 Upgrade. It requires prior knowledge
that the server supports HTTP/2 straight away. HTTPS requests
will still do HTTP/2 the standard way with negotiated protocol
version in the TLS handshake.
--http2-prior-knowledge requires that the underlying libcurl was
built to support HTTP/2. This option overrides --http1.1 and -0,
--http1.0 and --http2. Added in 7.49.0.
--http2
(HTTP) Tells curl to use HTTP version 2.
See also --no-alpn. --http2 requires that the underlying libcurl
was built to support HTTP/2. This option overrides --http1.1 and
-0, --http1.0 and --http2-prior-knowledge. Added in 7.33.0.
--ignore-content-length
(FTP HTTP) For HTTP, Ignore the Content-Length header. This is
particularly useful for servers running Apache 1.x, which will
report incorrect Content-Length for files larger than 2 giga-
bytes.
For FTP (since 7.46.0), skip the RETR command to figure out the
size before downloading a file.
-i, --include
Include the HTTP-header in the output. The HTTP-header includes
things like server-name, date of the document, HTTP-version and
more...
See also -v, --verbose.
-k, --insecure
(TLS) By default, every SSL connection curl makes is verified to
be secure. This option allows curl to proceed and operate even
for server connections otherwise considered insecure.
The server connection is verified by making sure the server's
certificate contains the right name and verifies successfully
using the cert store.
See this online resource for further details:
https://curl.haxx.se/docs/sslcerts.html
See also --proxy-insecure and --cacert.
--interface <name>
Perform an operation using a specified interface. You can enter
interface name, IP address or host name. An example could look
like:
curl --interface eth0:1 https://www.example.com/
If this option is used several times, the last one will be used.
See also --dns-interface.
-4, --ipv4
This option tells curl to resolve names to IPv4 addresses only,
and not for example try IPv6.
See also --http1.1 and --http2. This option overrides -6,
--ipv6.
-6, --ipv6
This option tells curl to resolve names to IPv6 addresses only,
and not for example try IPv4.
See also --http1.1 and --http2. This option overrides -6,
--ipv6.
-j, --junk-session-cookies
(HTTP) When curl is told to read cookies from a given file, this
option will make it discard all "session cookies". This will
basically have the same effect as if a new session is started.
Typical browsers always discard session cookies when they're
closed down.
See also -b, --cookie and -c, --cookie-jar.
--keepalive-time <seconds>
This option sets 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, recent AIX, HP-UX and more). This option has no
effect if --no-keepalive is used.
If this option is used several times, the last one will be used.
If unspecified, the option defaults to 60 seconds.
Added in 7.18.0.
--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 this option is used several times, the last one will be used.
--key <key>
(TLS SSH) Private key file name. Allows you to provide your pri-
vate key in this separate file. For SSH, if not specified, curl
tries the following candidates in order:
If this option is used several times, the last one will be used.
--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' will instead be used.
If this option is used several times, the last one will be used.
--krb requires that the underlying libcurl was built to support
Kerberos.
--libcurl <file>
Append this option to any ordinary curl command line, and you
will get a libcurl-using C source code written to the file that
does the equivalent of what your command-line operation does!
If this option is used several times, the last given file name
will be used.
Added in 7.16.1.
--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'd 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' will count the number as kilo-
bytes, 'm' or M' makes it megabytes, while 'g' or 'G' makes it
gigabytes. Examples: 200K, 3m and 1G.
If you also use the -Y, --speed-limit option, that option will
take precedence and might cripple the rate-limiting slightly, to
help keeping the speed-limit logic working.
If this option is used several times, the last one will be used.
-l, --list-only
(FTP POP3) (FTP) When listing an FTP directory, this switch
forces a name-only view. This is especially useful if the user
wants to machine-parse the contents of an FTP directory since
the normal directory view doesn't use a standard look or format.
When used like this, the option causes a 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.
(POP3) When retrieving a specific email from POP3, this switch
forces a LIST command to be performed instead of RETR. This is
particularly useful if the user wants to see if a specific mes-
sage id exists on the server and what size it is.
Note: When combined with -X, --request, this option can be used
to send an UIDL command instead, so the user may use the email's
unique identifier rather than it's message id to make the
request.
Added in 7.21.5.
--local-port <num/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 that will be busy at times so set-
ting this range to something too narrow might cause unnecessary
connection setup failures.
Added in 7.15.2.
--location-trusted
(HTTP) Like -L, --location, but will allow sending the name +
password to all hosts that the site may redirect to. This may or
may not introduce a security breach if the site redirects you to
a site to which you'll send your authentication info (which is
plaintext in the case of HTTP Basic authentication).
See also -u, --user.
-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 will make curl redo the request
on the new place. If used together with -i, --include or -I,
--head, headers from all requested pages will be shown. When
authentication is used, curl only sends its credentials to the
initial host. If a redirect takes curl to a different host, it
won't be able to intercept the user+password. See also --loca-
tion-trusted on how to change this. You can limit the amount of
redirects to follow by using the --max-redirs option.
When curl follows a redirect and the request is not a plain GET
(for example POST or PUT), it will do 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 will re-send the following
request using the same unmodified method.
You can tell curl to not change the non-GET request method to
GET after a 30x response by using the dedicated options for
that: --post301, --post302 and --post303.
--login-options <options>
(IMAP POP3 SMTP) Specify the login options to use during server
authentication.
You can use the 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 the login options please see RFC 2384, RFC 5092 and IETF
draft draft-earhart-url-smtp-00.txt
If this option is used several times, the last one will be used.
Added in 7.34.0.
--mail-auth <address>
(SMTP) Specify a single address. This will be used to specify
the authentication address (identity) of a submitted message
that is being relayed to another server.
See also --mail-rcpt and --mail-from. Added in 7.25.0.
--mail-from <address>
(SMTP) Specify a single address that the given mail should get
sent from.
See also --mail-rcpt and --mail-auth. Added in 7.20.0.
--mail-rcpt <address>
(SMTP) Specify a single address, user name or mailing list name.
Repeat this option several times to send to multiple recipients.
When performing a mail transfer, the recipient should specify a
valid email address to send the mail to.
When performing an address verification (VRFY command), the
recipient should be specified as the user name or user name and
domain (as per Section 3.5 of RFC5321). (Added in 7.34.0)
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". (Added in 7.34.0)
Added in 7.20.0.
-M, --manual
Manual. Display the huge help text.
--max-filesize <bytes>
Specify the maximum size (in bytes) of a file to download. If
the file requested is larger than this value, the transfer will
not start and curl will return with exit code 63.
NOTE: The file size is not always known prior to download, and
for such files this option has no effect even if the file trans-
fer ends up being larger than this given limit. This concerns
both FTP and HTTP transfers.
See also --limit-rate.
--max-redirs <num>
(HTTP) Set maximum number of redirection-followings allowed.
When -L, --location is used, is used to prevent curl from fol-
lowing redirections "in absurdum". By default, the limit is set
to 50 redirections. Set this option to -1 to make it unlimited.
If this option is used several times, the last one will be used.
-m, --max-time <time>
Maximum time in seconds that you allow the whole operation to
take. This is useful for preventing your batch jobs from hang-
ing for hours due to slow networks or links going down. Since
7.32.0, this option accepts decimal values, but the actual time-
out will decrease in accuracy as the specified timeout increases
in decimal precision.
If this option is used several times, the last one will be used.
See also --connect-timeout.
--metalink
This option can tell curl to parse and process a given URI as
Metalink file (both version 3 and 4 (RFC 5854) are supported)
and make use of the mirrors listed within for failover if there
are errors (such as the file or server not being available). It
will also verify the hash of the file after the download com-
pletes. The Metalink file itself is downloaded and processed in
memory and not stored in the local file system.
Example to use a remote Metalink file:
curl --metalink http://www.example.com/example.metalink
To use a Metalink file in the local file system, use FILE proto-
col (file://):
curl --metalink file://example.metalink
Please note that if FILE protocol is disabled, there is no way
to use a local Metalink file at the time of this writing. Also
note that if --metalink and -i, --include are used together,
--include will be ignored. This is because including headers in
the response will break Metalink parser and if the headers are
included in the file described in Metalink file, hash check will
fail.
--metalink requires that the underlying libcurl was built to
support metalink. Added in 7.27.0.
--negotiate
(HTTP) Enables 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 user name and password from the -u,
--user option aren't actually used.
If this option is used several times, only the first one is
used.
See also --basic and --ntlm and --anyauth and --proxy-negotiate.
--netrc-file <filename>
This option is similar to -n, --netrc, except that you provide
the path (absolute or relative) to the netrc file that Curl
should use. You can only specify one netrc file per invocation.
If several --netrc-file options are provided, the last one will
be used.
It will abide by --netrc-optional if specified.
This option overrides -n, --netrc. Added in 7.21.5.
--netrc-optional
Very similar to -n, --netrc, but this option makes the .netrc
usage optional and not mandatory as the -n, --netrc option does.
See also --netrc-file. This option overrides -n, --netrc.
-n, --netrc
Makes curl scan the .netrc (_netrc on Windows) file in the
user's home directory for login name and password. This is typi-
cally used for FTP on Unix. If used with HTTP, curl will enable
user authentication. See netrc(5) ftp(1) for details on the file
format. Curl will not complain if that file doesn't have the
right permissions (it should not be either world- or group-read-
able). The environment variable "HOME" is used to find the home
directory.
A quick and very simple example of how to setup a .netrc to
allow curl to FTP to the machine host.domain.com with user name
'myself' and password 'secret' should look similar to:
machine host.domain.com login myself password secret
-:, --next
Tells curl to 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 will reset all local options and only global ones
will have their values survive over to the operation following
the -:, --next instruction. Global options include -v, --ver-
bose, --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
Added in 7.36.0.
--no-alpn
(HTTPS) Disable the ALPN TLS extension. ALPN is enabled by
default 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.
See also --no-npn and --http2. --no-alpn requires that the
underlying libcurl was built to support TLS. Added in 7.36.0.
-N, --no-buffer
Disables the buffering of the output stream. In normal work sit-
uations, curl will use a standard buffered output stream that
will have the effect that it will output the data in chunks, not
necessarily exactly when the data arrives. Using this option
will disable that buffering.
Note that this is the negated option name documented. You can
thus use --buffer to enforce the buffering.
--no-keepalive
Disables 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.
--no-npn
(HTTPS) 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
support with the server during https sessions.
See also --no-alpn and --http2. --no-npn requires that the
underlying libcurl was built to support TLS. Added in 7.36.0.
--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.
Added in 7.16.0.
--noproxy <no-proxy-list>
Comma-separated list of hosts which do not 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 contains the
hostname, or the hostname itself. For example, local.com would
match local.com, local.com:80, and www.local.com, but not
www.notlocal.com.
Since 7.53.0, This option overrides the environment variables
that disable the proxy. If there's an environment variable dis-
abling a proxy, you can set noproxy list to "" to override it.
Added in 7.19.4.
--ntlm-wb
(HTTP) Enables NTLM much in the style --ntlm does, but hand over
the authentication to the separate binary ntlmauth application
that is executed when needed.
See also --ntlm and --proxy-ntlm.
--ntlm (HTTP) Enables 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 peo-
ple and implemented in curl based on their efforts. This kind of
behavior should not be endorsed, you should encourage everyone
who uses NTLM to switch to a public and documented authentica-
tion method instead, such as Digest.
If you want to enable NTLM for your proxy authentication, then
use --proxy-ntlm.
If this option is used several times, only the first one is
used.
See also --proxy-ntlm. --ntlm requires that the underlying
libcurl was built to support TLS. This option overrides --basic
and --negotiated and --digest and --anyauth.
--oauth2-bearer
(IMAP POP3 SMTP) Specify the Bearer Token for OAUTH 2.0 server
authentication. The Bearer Token is used in conjunction with the
user name which can be specified as part of the --url or -u,
--user options.
The Bearer Token and user name are formatted according to RFC
6750.
If this option is used several times, the last one will be used.
-o, --output <file>
Write output to <file> instead of stdout. If you are using {} or
[] to fetch multiple documents, you can use '#' followed by a
number in the <file> specifier. That variable will be 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].com -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 doesn't 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)
will force the output to be done to stdout.
See also -O, --remote-name and --remote-name-all and -J,
--remote-header-name.
--pass <phrase>
(SSH TLS) Passphrase for the private key
If this option is used several times, the last one will be used.
--path-as-is
Tell curl to not handle sequences of /../ or /./ in the given
URL path. Normally curl will squash or merge them according to
standards but with this option set you tell it not to do that.
Added in 7.42.0.
--pinnedpubkey <hashes>
(TLS) Tells curl to 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 sepa-
rated 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 will abort the connection
before sending or receiving any data.
PEM/DER support:
7.39.0: OpenSSL, GnuTLS and GSKit
7.43.0: NSS and wolfSSL/CyaSSL
7.47.0: mbedtls
7.49.0: PolarSSL sha256 support:
7.44.0: OpenSSL, GnuTLS, NSS and wolfSSL/CyaSSL.
7.47.0: mbedtls
7.49.0: PolarSSL Other SSL backends not supported.
If this option is used several times, the last one will be used.
--post301
(HTTP) Tells curl to respect RFC 7231/6.4.2 and not convert POST
requests into GET requests when following a 301 redirection. The
non-RFC behaviour is ubiquitous in web browsers, so curl does
the conversion by default to maintain consistency. However, a
server may require a POST to remain a POST after such a redi-
rection. This option is meaningful only when using -L, --loca-
tion.
See also --post302 and --post303 and -L, --location. Added in
7.17.1.
--post302
(HTTP) Tells curl to respect RFC 7231/6.4.3 and not convert POST
requests into GET requests when following a 302 redirection. The
non-RFC behaviour is ubiquitous in web browsers, so curl does
the conversion by default to maintain consistency. However, a
server may require a POST to remain a POST after such a redi-
rection. This option is meaningful only when using -L, --loca-
tion.
See also --post301 and --post303 and -L, --location. Added in
7.19.1.
--post303
(HTTP) Tells curl to respect RFC 7231/6.4.4 and not convert POST
requests into GET requests when following a 303 redirection. The
non-RFC behaviour is ubiquitous in web browsers, so curl does
the conversion by default to maintain consistency. However, a
server may require a POST to remain a POST after such a redi-
rection. This option is meaningful only when using -L, --loca-
tion.
See also --post302 and --post301 and -L, --location. Added in
7.26.0.
--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 will make curl
default 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 this option is used several times, the last one will be used.
Added in 7.52.0.
-#, --progress-bar
Make curl display transfer progress as a simple progress bar
instead 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, it will instead output one
'#' character for every 1024 bytes transferred.
--proto-default <protocol>
Tells curl to use protocol for any URL missing a scheme name.
Example:
curl --proto-default https ftp.mozilla.org
An unknown or unsupported protocol causes error CURLE_UNSUP-
PORTED_PROTOCOL (1).
This option does not change the default proxy protocol (http).
Without this option curl would make a guess based on the host,
see --url for details.
Added in 7.45.0.
--proto-redir <protocols>
Tells curl to limit what protocols it may use on redirect. Pro-
tocols 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 will allow all protocols on redirect except sev-
eral disabled for security reasons: Since 7.19.4 FILE and SCP
are disabled, and since 7.40.0 SMB and SMBS are also disabled.
Specifying all or +all enables all protocols on redirect,
including those disabled for security.
Added in 7.20.2.
--proto <protocols>
Tells curl to limit what protocols it may use in the transfer.
Protocols are evaluated left to right, are comma separated, and
are each a protocol name or
+ Permit this protocol in addition to protocols already permit-
ted (this is the default if no modifier is used).
- Deny this protocol, removing it from the list of protocols
already permitted.
= Permit only this protocol (ignoring the list already permit-
ted), though subject to later modification by subsequent
entries in the comma separated list.
For example:
--proto -ftps uses the default protocols, but disables ftps
--proto -all,https,+http
only enables http and https
--proto =http,https
also only enables http and https
Unknown protocols produce a warning. This allows scripts to safely rely
on being able to disable potentially dangerous protocols, without rely-
ing 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.
See also --proto-redir and --proto-default. Added in 7.20.2.
--proxy-anyauth
Tells curl to pick a suitable authentication method when commu-
nicating with the given HTTP proxy. This might cause an extra
request/response round-trip.
See also -x, --proxy and --proxy-basic and --proxy-digest. Added
in 7.13.2.
--proxy-basic
Tells curl to 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 proxies.
See also -x, --proxy and --proxy-anyauth and --proxy-digest.
--proxy-cacert <file>
Same as --cacert but used in HTTPS proxy context.
See also --proxy-capath and --cacert and --capath and -x,
--proxy. Added in 7.52.0.
--proxy-capath <dir>
Same as --capath but used in HTTPS proxy context.
See also --proxy-cacert and -x, --proxy and --capath. Added in
7.52.0.
--proxy-cert-type <type>
Same as --cert-type but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-cert <cert[:passwd]>
Same as -E, --cert but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-ciphers <list>
Same as --ciphers but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-crlfile <file>
Same as --crlfile but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-digest
Tells curl to use HTTP Digest authentication when communicating
with the given proxy. Use --digest for enabling HTTP Digest with
a remote host.
See also -x, --proxy and --proxy-anyauth and --proxy-basic.
--proxy-header <header>
(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 will make 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
returns, they will only mess things up for you.
Headers specified with this option will not be included in
requests that curl knows will not be sent to a proxy.
This option can be used multiple times to add/replace/remove
multiple headers.
Added in 7.37.0.
--proxy-insecure
Same as -k, --insecure but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-key-type <type>
Same as --key-type but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-key <key>
Same as --key but used in HTTPS proxy context.
--proxy-negotiate
Tells curl to use HTTP Negotiate (SPNEGO) authentication when
communicating with the given proxy. Use --negotiate for enabling
HTTP Negotiate (SPNEGO) with a remote host.
See also --proxy-anyauth and --proxy-basic. Added in 7.17.1.
--proxy-ntlm
Tells curl to use HTTP NTLM authentication when communicating
with the given proxy. Use --ntlm for enabling NTLM with a remote
host.
See also --proxy-negotiate and --proxy-anyauth.
--proxy-pass <phrase>
Same as --pass but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-service-name <name>
This option allows you to change the service name for proxy
negotiation.
Added in 7.43.0.
--proxy-ssl-allow-beast
Same as --ssl-allow-beast but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-tlsauthtype <type>
Same as --tlsauthtype but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-tlspassword <string>
Same as --tlspassword but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-tlsuser <name>
Same as --tlsuser but used in HTTPS proxy context.
Added in 7.52.0.
--proxy-tlsv1
Same as -1, --tlsv1 but used in HTTPS proxy context.
Added in 7.52.0.
-U, --proxy-user <user:password>
Specify the user name and password to use for proxy authentica-
tion.
If you use a Windows SSPI-enabled curl binary and do either
Negotiate or NTLM authentication then you can tell curl to
select the user name and password from your environment by spec-
ifying a single colon with this option: "-U :".
If this option is used several times, the last one will be used.
-x, --proxy [protocol://]host[:port]
Use the specified proxy.
The proxy string can be specified with a protocol:// prefix. No
protocol specified or http:// will be treated as HTTP proxy. Use
socks4://, socks4a://, socks5:// or socks5h:// to request a spe-
cific SOCKS version to be used. (The protocol support was added
in curl 7.21.7)
HTTPS proxy support via https:// protocol prefix was added in
7.52.0 for OpenSSL, GnuTLS and NSS.
Unrecognized and unsupported proxy protocols cause an error
since 7.52.0. Prior versions may ignore the protocol and use
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's an environment variable setting a
proxy, you can set proxy to "" to override it.
All operations that are performed over an HTTP proxy will trans-
parently be converted to HTTP. It means that certain protocol
specific operations might not be available. This is not the case
if you can tunnel through the proxy, as one with the -p, --prox-
ytunnel 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 exact same way as the proxy
environment variables, including the protocol prefix (http://)
and the embedded user + password.
If this option is used several times, the last one will be used.
--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 will
specify an HTTP 1.0 protocol instead of the default HTTP 1.1.
-p, --proxytunnel
When an HTTP proxy is used -x, --proxy, this option will cause
non-HTTP protocols to attempt to tunnel through the proxy
instead of merely using it to do HTTP-like operations. The tun-
nel approach is made with the HTTP proxy CONNECT request and
requires that the proxy allows direct connect 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.
See also -x, --proxy.
--pubkey <key>
(SFTP SCP) Public key file name. Allows you to provide your pub-
lic key in this separate file.
If this option is used several times, the last one will be used.
(As of 7.39.0, curl attempts to automatically extract the public
key from the private key file, so passing this option is gener-
ally not required. Note that this public key extraction requires
libcurl to be linked against a copy of libssh2 1.2.8 or higher
that is itself linked against OpenSSL.)
-Q, --quote
(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 '-'. To make commands be sent after
curl has changed the working directory, just before the transfer
command(s), prefix the command with a '+' (this is only sup-
ported for FTP). You may specify any number of commands.
If the server returns failure for one of the commands, the
entire operation will be aborted. You must send syntactically
correct FTP commands as RFC 959 defines to FTP servers, or one
of the commands listed below to SFTP servers.
This option can be used multiple times. When speaking to an FTP
server, prefix the command with an asterisk (*) to make curl
continue even if the command fails as by default curl will stop
at first failure.
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:
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
directory_name operand.
pwd The pwd command returns the absolute pathname of the cur-
rent 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.
--random-file <file>
Specify the path name to file containing what will be considered
as random data. The data may be used to seed the random engine
for SSL connections. See also the --egd-file option.
-r, --range <range>
(HTTP FTP SFTP FILE) Retrieve a byte range (i.e a partial docu-
ment) from a 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 this will cause the server to reply with a mul-
tipart response!
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 will be unspec-
ified, depending on the server's configuration.
You should also be aware that many HTTP/1.1 servers do not have
this feature enabled, so that when you attempt to get a range,
you'll instead get the whole document.
FTP and SFTP range downloads only support the simple 'start-
stop' syntax (optionally with one of the numbers omitted). FTP
use depends on the extended FTP command SIZE.
If this option is used several times, the last one will be used.
--raw (HTTP) When used, it disables all internal HTTP decoding of con-
tent or transfer encodings and instead makes them passed on
unaltered, raw.
Added in 7.16.2.
-e, --referer <URL>
(HTTP) Sends the "Referrer Page" information to the HTTP server.
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 don't set an initial -e, --referer.
If this option is used several times, the last one will be used.
See also -A, --user-agent and -H, --header.
-J, --remote-header-name
(HTTP) This option tells the -O, --remote-name option to use the
server-specified Content-Disposition filename instead of
extracting a filename from the URL.
If the server specifies a file name and a file with that name
already exists in the current working directory it will not be
overwritten and an error will occur. If the server doesn't spec-
ify a file name then this option has no effect.
There's no attempt to decode %-sequences (yet) in the provided
file name, so this option may provide you with rather unexpected
file names.
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 possibly be loaded automatically by Win-
dows or some third party software.
--remote-name-all
This option changes the default action for all given URLs to be
dealt with as if -O, --remote-name were used for each one. So if
you want to disable that for a specific URL after --remote-name-
all has been used, you must use "-o -" or --no-remote-name.
Added in 7.19.0.
-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 will be 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 option.
The remote file name to use for saving is extracted from the
given URL, nothing else, and if it already exists it will be
overwritten. If you want the server to be able to choose the
file name refer to -J, --remote-header-name which can be used in
addition to this option. If the server chooses a file name and
that name already exists it will not be overwritten.
There is no URL decoding done on the file name. If it has %20 or
other URL encoded parts of the name, they will end up as-is as
file name.
You may use this option as many times as the number of URLs you
have.
-R, --remote-time
When used, this will make curl attempt to figure out the time-
stamp of the remote file, and if that is available make the
local file get that same timestamp.
-X, --request <command>
(HTTP) Specifies a custom request method to use when communicat-
ing with the HTTP server. The specified request method will be
used instead of the method otherwise used (which defaults to
GET). Read the HTTP 1.1 specification for details and explana-
tions. Common additional HTTP requests include PUT and DELETE,
but related technologies like WebDAV offers PROPFIND, COPY, MOVE
and more.
Normally you don't need this option. All sorts of GET, HEAD,
POST and PUT requests are rather invoked by using dedicated com-
mand line options.
This option only changes the actual word used in the HTTP
request, it does not alter the way curl behaves. So for example
if you want to make a proper HEAD request, using -X HEAD will
not suffice. You need to use the -I, --head option.
The method string you set with -X, --request will be used for
all requests, which if you for example use -L, --location may
cause unintended side-effects when curl doesn't 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. (Added in 7.26.0)
(IMAP) Specifies a custom IMAP command to use instead of LIST.
(Added in 7.30.0)
(SMTP) Specifies a custom SMTP command to use instead of HELP or
VRFY. (Added in 7.34.0)
If this option is used several times, the last one will be used.
--resolve <host:port:address>
Provide a custom address for a specific host and port pair.
Using this, you can make the curl requests(s) use a specified
address 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 will be used for. It means
you need several entries if you want to provide address for the
same host but different ports.
The provided address set by this option will be used even if -4,
--ipv4 or -6, --ipv6 is set to make curl use another IP version.
This option can be used many times to add many host names to
resolve.
Added in 7.21.3.
--retry-connrefused
In addition to the other conditions, consider ECONNREFUSED as a
transient error too for --retry. This option is used together
with --retry.
Added in 7.52.0.
--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
default backoff time algorithm between retries). This option is
only interesting if --retry is also used. Setting this delay to
zero will make curl use the default backoff time.
If this option is used several times, the last one will be used.
Added in 7.12.3.
--retry-max-time <seconds>
The retry timer is reset before the first transfer attempt.
Retries will be done as usual (see --retry) as long as the timer
hasn't reached this given limit. Notice that if the timer hasn't
reached the limit, the request will be made and while perform-
ing, 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 this option is used several times, the last one will be used.
Added in 7.12.3.
--retry <num>
If a transient error is returned when curl tries to perform a
transfer, it will retry this number of times before giving up.
Setting the number to 0 makes curl do no retries (which is the
default). Transient error means either: a timeout, an FTP 4xx
response code or an HTTP 5xx response code.
When curl is about to retry a transfer, it will first wait one
second and then for all forthcoming retries it will double the
waiting time until it reaches 10 minutes which then will be the
delay 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.
If this option is used several times, the last one will be used.
Added in 7.12.3.
--sasl-ir
Enable initial response in SASL authentication.
Added in 7.31.0.
--service-name <name>
This option allows you to change the service name for SPNEGO.
Examples: --negotiate --service-name sockd would use
sockd/server-name.
Added in 7.43.0.
-S, --show-error
When used with -s, --silent, it makes curl show an error message
if it fails.
-s, --silent
Silent or quiet mode. Don't show progress meter or error mes-
sages. Makes Curl mute. It will still output 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.
See also -v, --verbose and --stderr.
--socks4 <host[:port]>
Use the specified SOCKS4 proxy. If the port number is not speci-
fied, it is assumed at port 1080.
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
Since 7.21.7, this option is superfluous since you can specify a
socks4 proxy with -x, --proxy using a socks4:// protocol prefix.
Since 7.52.0, --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 con-
nects (through SOCKS) to the HTTP or HTTPS proxy.
If this option is used several times, the last one will be used.
Added in 7.15.2.
--socks4a <host[:port]>
Use the specified SOCKS4a proxy. If the port number is not spec-
ified, it is assumed at port 1080.
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
Since 7.21.7, this option is superfluous since you can specify a
socks4a proxy with -x, --proxy using a socks4a:// protocol pre-
fix.
Since 7.52.0, --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 con-
nects (through SOCKS) to the HTTP or HTTPS proxy.
If this option is used several times, the last one will be used.
Added in 7.18.0.
--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.
Added in 7.19.4.
--socks5-gssapi-service <name>
The default service name for a socks server is rcmd/server-fqdn.
This option allows you to change it.
Examples: --socks5 proxy-name --socks5-gssapi-service sockd
would use sockd/proxy-name --socks5 proxy-name --socks5-gssapi-
service sockd/real-name would use sockd/real-name for cases
where the proxy-name does not match the principal name.
Added in 7.19.4.
--socks5-hostname <host[:port]>
Use the specified SOCKS5 proxy (and let the proxy resolve the
host name). If the port number is not specified, it is assumed
at port 1080.
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
Since 7.21.7, this option is superfluous since you can specify a
socks5 hostname proxy with -x, --proxy using a socks5h:// proto-
col prefix.
Since 7.52.0, --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 con-
nects (through SOCKS) to the HTTP or HTTPS proxy.
If this option is used several times, the last one will be used.
Added in 7.18.0.
--socks5 <host[:port]>
Use the specified SOCKS5 proxy - but resolve the host name
locally. If the port number is not specified, it is assumed at
port 1080.
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
Since 7.21.7, this option is superfluous since you can specify a
socks5 proxy with -x, --proxy using a socks5:// protocol prefix.
Since 7.52.0, --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 con-
nects (through SOCKS) to the HTTP or HTTPS proxy.
If this option is used several times, the last one will be used.
This option (as well as --socks4) does not work with IPV6, FTPS
or LDAP.
Added in 7.18.0.
-Y, --speed-limit <speed>
If a download is slower than this given speed (in bytes per sec-
ond) for speed-time seconds it gets aborted. speed-time is set
with -y, --speed-time and is 30 if not set.
If this option is used several times, the last one will be used.
-y, --speed-time <seconds>
If a download is slower than speed-limit bytes per second during
a speed-time period, the download gets aborted. If speed-time is
used, the default speed-limit will be 1 unless set with -Y,
--speed-limit.
This option controls transfers and thus will not affect slow
connects etc. If this is a concern for you, try the --connect-
timeout option.
If this option is used several times, the last one will be used.
--ssl-allow-beast
This option tells curl to not work around a security flaw in the
SSL3 and TLS1.0 protocols known as BEAST. If this option isn't
used, the SSL layer may use workarounds known to cause interop-
erability problems with some older SSL implementations. WARNING:
this option loosens the SSL security, and by using this flag you
ask for exactly that.
Added in 7.25.0.
--ssl-no-revoke
(WinSSL) This option tells curl to disable certificate revoca-
tion checks. WARNING: this option loosens the SSL security, and
by using this flag you ask for exactly that.
Added in 7.44.0.
--ssl-reqd
(FTP IMAP POP3 SMTP) Require SSL/TLS for the connection. Termi-
nates the connection if the server doesn't support SSL/TLS.
This option was formerly known as --ftp-ssl-reqd.
Added in 7.20.0.
--ssl (FTP IMAP POP3 SMTP) Try to use SSL/TLS for the connection.
Reverts to a non-secure connection if the server doesn't support
SSL/TLS. See also --ftp-ssl-control and --ssl-reqd for differ-
ent levels of encryption required.
This option was formerly known as --ftp-ssl (Added in 7.11.0).
That option name can still be used but will be removed in a
future version.
Added in 7.20.0.
-2, --sslv2
(SSL) Forces curl to use SSL version 2 when negotiating with a
remote SSL server. Sometimes curl is built without SSLv2 sup-
port. SSLv2 is widely considered insecure (see RFC 6176).
See also --http1.1 and --http2. -2, --sslv2 requires that the
underlying libcurl was built to support TLS. This option over-
rides -3, --sslv3 and -1, --tlsv1 and --tlsv1.1 and --tlsv1.2.
-3, --sslv3
(SSL) Forces curl to use SSL version 3 when negotiating with a
remote SSL server. Sometimes curl is built without SSLv3 sup-
port. SSLv3 is widely considered insecure (see RFC 7568).
See also --http1.1 and --http2. -3, --sslv3 requires that the
underlying libcurl was built to support TLS. This option over-
rides -2, --sslv2 and -1, --tlsv1 and --tlsv1.1 and --tlsv1.2.
--stderr
Redirect all writes to stderr to the specified file instead. If
the file name is a plain '-', it is instead written to stdout.
If this option is used several times, the last one will be used.
See also -v, --verbose and -s, --silent.
--suppress-connect-headers
When -p, --proxytunnel is used and a CONNECT request is made
don't output proxy CONNECT response headers. This option is
meant to be used with -D, --dump-header or -i, --include which
are used to show protocol headers in the output. It has no
effect on debug options such as -v, --verbose or --trace, or any
statistics.
See also -D, --dump-header and -i, --include and -p, --proxytun-
nel.
--tcp-fastopen
Enable use of TCP Fast Open (RFC7413).
Added in 7.49.0.
--tcp-nodelay
Turn on the TCP_NODELAY option. See the curl_easy_setopt(3) man
page for details about this option.
Since 7.50.2, curl sets this option by default and you need to
explicitly switch it off if you don't want it on.
Added in 7.11.2.
-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.
--tftp-blksize <value>
(TFTP) Set TFTP BLKSIZE option (must be >512). This is the block
size that curl will try to use when transferring data to or from
a TFTP server. By default 512 bytes will be used.
If this option is used several times, the last one will be used.
Added in 7.20.0.
--tftp-no-options
(TFTP) Tells curl not to send TFTP options requests.
This option improves interop with some legacy servers that do
not acknowledge or properly implement TFTP options. When this
option is used --tftp-blksize is ignored.
Added in 7.48.0.
-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 doesn't match any internal ones, it is taken as a filename
and tries to get the modification date (mtime) from <file>
instead. See the curl_getdate(3) man pages for date expression
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 this option is used several times, the last one will be used.
--tls-max <VERSION>
(SSL) VERSION defines maximum supported TLS version. A minimum
is defined by arguments tlsv1.0 or tlsv1.1 or tlsv1.2.
default
Use up to 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.
See also --tlsv1.0 and --tlsv1.1 and --tlsv1.2. --tls-max requires that
the underlying libcurl was built to support TLS. Added in 7.54.0.
--tlsauthtype <type>
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".
Added in 7.21.4.
--tlspassword
Set password for use with the TLS authentication method speci-
fied with --tlsauthtype. Requires that --tlsuser also be set.
Added in 7.21.4.
--tlsuser <name>
Set username for use with the TLS authentication method speci-
fied with --tlsauthtype. Requires that --tlspassword also is
set.
Added in 7.21.4.
--tlsv1.0
(TLS) Forces curl to use TLS version 1.0 when connecting to a
remote TLS server.
Added in 7.34.0.
--tlsv1.1
(TLS) Forces curl to use TLS version 1.1 when connecting to a
remote TLS server.
Added in 7.34.0.
--tlsv1.2
(TLS) Forces curl to use TLS version 1.2 when connecting to a
remote TLS server.
Added in 7.34.0.
--tlsv1.3
(TLS) Forces curl to use TLS version 1.3 when connecting to a
remote TLS server.
Note that TLS 1.3 is only supported by a subset of TLS backends.
At the time of writing this, those are BoringSSL and NSS only.
Added in 7.52.0.
-1, --tlsv1
(SSL) Tells curl to use TLS version 1.x when negotiating with a
remote TLS server. That means TLS version 1.0, 1.1 or 1.2.
See also --http1.1 and --http2. -1, --tlsv1 requires that the
underlying libcurl was built to support TLS. This option over-
rides --tlsv1.1 and --tlsv1.2 and --tlsv1.3.
--tr-encoding
(HTTP) Request a compressed Transfer-Encoding response using one
of the algorithms curl supports, and uncompress the data while
receiving it.
Added in 7.21.6.
--trace-ascii <file>
Enables a full trace dump of all incoming and outgoing data,
including descriptive information, to the given output file. Use
"-" as filename to have the output sent to stdout.
This is very 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.
If this option is used several times, the last one will be used.
This option overrides --trace and -v, --verbose.
--trace-time
Prepends a time stamp to each trace or verbose line that curl
displays.
Added in 7.14.0.
--trace <file>
Enables a full trace dump of all incoming and outgoing data,
including descriptive information, to the given output file. Use
"-" as filename to have the output sent to stdout. Use "%" as
filename to have the output sent to stderr.
If this option is used several times, the last one will be used.
This option overrides -v, --verbose and --trace-ascii.
--unix-socket <path>
(HTTP) Connect through this Unix domain socket, instead of using
the network.
Added in 7.40.0.
-T, --upload-file <file>
This transfers the specified local file to the remote URL. If
there is no file part in the specified URL, curl will append the
local file name. NOTE that you must use a trailing / on the last
directory to really prove to Curl that there is no file name or
curl will think that your last directory name is the remote file
name to use. That will most likely cause the upload operation to
fail. If this is used on an HTTP(S) server, the PUT command will
be used.
Use the file name "-" (a single dash) to use stdin instead of a
given file. Alternately, the file name "." (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.
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, like this:
curl --upload-file "{file1,file2}" http://www.example.com
or even
curl -T "img[1-1000].png" ftp://ftp.example.com/upload/
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
will not transcode nor encode it further in any way.
--url <url>
Specify a URL to fetch. This option is mostly handy when you
want to specify URL(s) in a config file.
If the given URL is missing a scheme name (such as "http://" or
"ftp://" etc) then curl will make a guess based on the host. If
the outermost sub-domain name matches DICT, FTP, IMAP, LDAP,
POP3 or SMTP then that protocol will be used, otherwise HTTP
will be used. Since 7.45.0 guessing can be disabled by setting a
default protocol, see --proto-default for details.
This option may be used any number of times. To control where
this URL is written, use the -o, --output or the -O, --remote-
name options.
-B, --use-ascii
(FTP LDAP) Enable ASCII transfer. 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.
-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 can also be set with the -H, --header option
of course.
If this option is used several times, the last one will be used.
-u, --user <user:password>
Specify the user name and password to use for server authentica-
tion. Overrides -n, --netrc and --netrc-optional.
If you simply specify the user name, curl will prompt for a
password.
The user name and passwords are split up on the first colon,
which makes it impossible to use a colon in the user name with
this option. The password can, still.
When using Kerberos V5 with a Windows based server you should
include the Windows domain name in the user name, in order for
the server to successfully obtain a Kerberos Ticket. If you
don't then the initial authentication handshake may fail.
When using NTLM, the user name can be specified simply as the
user name, 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 user name and password from your envi-
ronment by specifying a single colon with this option: "-u :".
If this option is used several times, the last one will be used.
-v, --verbose
Makes curl verbose during the operation. Useful 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, --include might
be the option you're looking for.
If you think this option still doesn't give you enough details,
consider using --trace or --trace-ascii instead.
Use -s, --silent to make curl really quiet.
See also -i, --include. This option overrides --trace and
--trace-ascii.
-V, --version
Displays 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.
The second line (starts with "Protocols:") shows all protocols
that libcurl reports to support.
The third line (starts with "Features:") shows specific features
libcurl reports to offer. Available features include:
IPv6 You can use IPv6 with this.
krb4 Krb4 for FTP is supported.
SSL SSL versions of various protocols are supported, such as
HTTPS, FTPS, POP3S and so on.
libz Automatic decompression of compressed files over HTTP is
supported.
NTLM NTLM authentication is supported.
Debug This curl uses a libcurl built with Debug. This enables
more error-tracking and memory debugging etc. For curl-
developers only!
AsynchDNS
This curl uses asynchronous name resolves. Asynchronous
name resolves can be done using either the c-ares or the
threaded resolver backends.
SPNEGO SPNEGO authentication is supported.
Largefile
This curl supports transfers of large files, files larger
than 2GB.
IDN This curl supports IDN - international domain names.
GSS-API
GSS-API is supported.
SSPI SSPI is supported.
TLS-SRP
SRP (Secure Remote Password) authentication is supported
for TLS.
HTTP2 HTTP/2 support has been built-in.
UnixSockets
Unix sockets support is provided.
HTTPS-proxy
This curl is built to support HTTPS proxy.
Metalink
This curl supports Metalink (both version 3 and 4 (RFC
5854)), which describes mirrors and hashes. curl will
use mirrors for failover if there are errors (such as the
file or server not being available).
PSL PSL is short for Public Suffix List and means that this
curl has been built with knowledge about "public suf-
fixes".
-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 will be substituted
by the value or text that curl thinks fit, as described below.
All variables are specified as %{variable_name} and to output a
normal % you just write them as