===== URL
The URL syntax is protocol-dependent. You'll find a detailed description 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 example, 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 mul‐
tiple connects / 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 ter‐
minal, 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 [file] 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.
===== 命令支持的选项及含义
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 spec‐
ify 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.)
--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 --nego‐
tiate.
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 point‐
less, 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
certificate 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 speci‐
fied, 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 nickname 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 cer‐
tificate/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://www.openssl.org/docs/apps/ciphers.html
NSS ciphers are done differently than OpenSSL and GnuTLS. The full list of NSS ciphers is in the NSSCipherSuite entry at this
URL:
https://git.fedorahosted.org/cgit/mod_nss.git/plain/docs/mod_nss.html#Directives
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 config 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 config 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 col‐
umn 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 '%USERPROFILE%\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 connects
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 hostname/port that is used for TLS/SSL (e.g. SNI, certificate verifi‐
cation) 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, meaning "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 operations. 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 Revocation 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 processing 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 interpretation 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 command 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. Posting 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 pol‐
icy.
always Unconditionally allow the server to delegate.
--digest
(HTTP) Enables HTTP Digest authentication. This is an authentication 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
extensions 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 <interface>. 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 con‐
nections.
See also --random-file.
--engine <name>
(TLS) Select the OpenSSL crypto engine to use for cipher operations. 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 first detected 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 successful transfers.
Using this option, curl will instead return an error on the first transfers that fails, independent on the amount of more URLs
that are given on the command line. This way, no transfer failures go undetected by scripts and similar.
This option will apply for all given URLs even if you use -:, --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 prevent 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 Transport (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 pos‐
sibility 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 filename. 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 double-quotes like:
curl -F "file=@\"localfile\";filename=\"nameinpost\"" example.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 com‐
mands. 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 commands.
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 connecting 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. Disable the use of PORT with --ftp-pasv. Disable the attempt to use
the EPRT command instead of PORT by using --disable-eprt. EPRT is really PORT++.
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
specify a port range, from a lower to a higher number. A single number works as well, but do note that it increases the risk of fail‐
ure 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 commu‐
nication will be unencrypted. This allows NAT routers to follow 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 support 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 '?' separa‐
tor.
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 perfectly well what you're doing. Remove an internal header by giving
a replacement without content on the right side of the colon, as in: -H "Host:". If you send the custom header with no-value
then its header must be terminated with a semicolon, such as -H "X-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 headers 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 gigabytes.
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) This option explicitly allows curl to perform "insecure" SSL connections and transfers. All SSL connections are attempted
to be made secure by using the CA certificate bundle installed by default. This makes all connections considered "insecure"
fail unless -k, --insecure is used.
See this online resource for further details:
https://curl.haxx.se/docs/sslcerts.html
--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 provided 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 private 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 message 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 setting 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 fol‐
lowing 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 recipi‐
ents.
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 recipient 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 follow‐
ing 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 hanging
for hours due to slow networks or links going down. Since 7.32.0, this option accepts decimal values, but the actual timeout
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 completes. 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 protocol (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 support. 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 <filemame>
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 typically
used for FTP on Unix. If used with HTTP, curl will enable user authentication. See netrc(5) ftp(1) for details on the file for‐
mat. Curl will not complain if that file doesn't have the right permissions (it should not be either world- or group-readable).
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, --verbose and --fail-early.
For example, you can do both a GET and a POST in a single command 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 negotiate 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 situations, 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 otherwis 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.
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 people 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 directories 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 con‐
tains 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 public 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 redirection. This option is meaningful only when using -L, --location.
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 redirection. This option is meaningful only when using -L, --location.
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 redirection. This option is meaningful only when using -L, --location.
See also --post302 and --post301 and -L, --location. Added in 7.26.0.
--preproxy [protocol://]host[:port]
Use the specified proxy before connecting to the ordinary proxy. Hence pre proxy. A pre proxy must be a SOCKS speaking proxy.
The pre proxy string should be specified with a protocol:// prefix 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 char‐
acters 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_UNSUPPORTED_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. Protocols denied by --proto are not overridden by this option. See
--proto for how protocols are represented.
Example, allow only HTTP and HTTPS on redirect:
curl --proto-redir -all,http,https http://example.com
By default curl will allow all protocols on redirect except several 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 permitted (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 permitted), 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 relying upon support for that protocol being built into curl to avoid an error.
This option can be used multiple times, in which case the effect is the same as concatenating the protocols into one instance of the
option.
See also --proto-redir and --proto-default. Added in 7.20.2.
--proxy-anyauth
Tells curl to pick a suitable authentication method when communicating 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 communication 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 authentication.
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 specifying 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 to specify alternative proxy protocols. Use socks4://, socks4a://,
socks5:// or socks5h:// to request the specific SOCKS version to be used. No protocol specified, http:// and all others will be
treated as HTTP proxies. (The protocol support was added in curl 7.21.7)
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 transparently 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,
--proxytunnel option.
User and password that might be provided in the proxy string are URL decoded by curl. This allows you to pass in special char‐
acters 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 tunnel 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.
See also -x, --proxy.
--pubkey <key>
(SFTP SCP) Public key file name. Allows you to provide your public 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 gen‐
erally 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 supported 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 cor‐
rect 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 characters. 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 oper‐
and. 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 operand. 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 location.
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 current working directory.
rename source target
The rename command renames the file or directory named by the source operand to the destination path named by the target
operand.
rm file
The rm command removes the file specified by the file operand.
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 document) 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 multipart 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 unspecified, 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 content 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 specify 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 Windows 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 over‐
written. If you want the server to be able to choose the file name refer to -J, --remote-header-name which can be used in addi‐
tion 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 timestamp 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 communicating 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 ver‐
sion.
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 messages. Makes Curl mute. It will still output the data you ask for,
potentially even to the terminal/stdout unless you redirect it.
See also -v, --verbose and --stderr.
--socks4 <host[:port]>
Use the specified SOCKS4 proxy. 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 socks4 proxy with -x, --proxy using a socks4:// protocol pre‐
fix.
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 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 socks4a proxy with -x, --proxy using a socks4a:// protocol
prefix.
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 negotiated. 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 protec‐
tion 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-ser‐
vice 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:// pro‐
tocol prefix.
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 pre‐
fix.
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 second) 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 interoperability 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 revocation 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. Terminates 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 different 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.
--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 explictitly 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 file‐
name 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.
--tlsauthtype <type>
Set TLS authentication type. Currently, the only supported option is "SRP", for TLS-SRP (RFC 5054). If --tlsuser and --tlspass‐
word 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 specified with --tlsauthtype. Requires that --tlsuser also be set.
Added in 7.21.4.
--tlsuser <name>
Set username for use with the TLS authentication method specified 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 opera‐
tion 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 command 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 supported 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 an 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 sin‐
gle 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 authentication. 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 Kerberos V5, Negotiate, NTLM or Digest authentication then you can
tell curl to select the user name and password from your environment 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-develop‐
ers 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 mir‐
rors 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 suffixes".
-w, --write-out <format>
Make curl display information on stdout after a completed transfer. 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 %%. You can output a newline by
using \n, a carriage return with \r and a tab space with \t.
NOTE: The %-symbol is a special symbol in the win32-environment, where all occurrences of % must be doubled when using this
option.
The variables available are:
content_type The Content-Type of the requested document, if there was any.
filename_effective
The ultimate filename that curl writes out to. This is only meaningful if curl is told to write to a file with
the -O, --remote-name or -o, --output option. It's most useful in combination with the -J, --remote-header-name
option. (Added in 7.26.0)
ftp_entry_path The initial path curl ended up in when logging on to the remote FTP server. (Added in 7.15.4)
http_code The numerical response code that was found in the last retrieved HTTP(S) or FTP(s) transfer. In 7.18.2 the alias
response_code was added to show the same info.
http_connect The numerical code that was found in the last response (from a proxy) to a curl CONNECT request. (Added in
7.12.4)
http_version The http version that was effectively used. (Added in 7.50.0)
local_ip The IP address of the local end of the most recently done connection - can be either IPv4 or IPv6 (Added in
7.29.0)
local_port The local port number of the most recently done connection (Added in 7.29.0)
num_connects Number of new connects made in the recent transfer. (Added in 7.12.3)
num_redirects Number of redirects that were followed in the request. (Added in 7.12.3)
redirect_url When an HTTP request was made without -L to follow redirects, this variable will show the actual URL a redirect
would take you to. (Added in 7.18.2)
remote_ip The remote IP address of the most recently done connection - can be either IPv4 or IPv6 (Added in 7.29.0)
remote_port The remote port number of the most recently done connection (Added in 7.29.0)
scheme The URL scheme (sometimes called protocol) that was effectively used (Added in 7.52.0)
size_download The total amount of bytes that were downloaded.
size_header The total amount of bytes of the downloaded headers.
size_request The total amount of bytes that were sent in the HTTP request.
size_upload The total amount of bytes that were uploaded.
speed_download The average download speed that curl measured for the complete download. Bytes per second.
speed_upload The average upload speed that curl measured for the complete upload. Bytes per second.
ssl_verify_result
The result of the SSL peer certificate verification that was requested. 0 means the verification was successful.
(Added in 7.19.0)
time_appconnect
The time, in seconds, it took from the start until the SSL/SSH/etc connect/handshake to the remote host was com‐
pleted. (Added in 7.19.0)
time_connect The time, in seconds, it took from the start until the TCP connect to the remote host (or proxy) was completed.
time_namelookup
The time, in seconds, it took from the start until the name resolving was completed.
time_pretransfer
The time, in seconds, it took from the start until the file transfer was just about to begin. This includes all
pre-transfer commands and negotiations that are specific to the particular protocol(s) involved.
time_redirect The time, in seconds, it took for all redirection steps include name lookup, connect, pretransfer and transfer
before the final transaction was started. time_redirect shows the complete execution time for multiple redirec‐
tions. (Added in 7.12.3)
time_starttransfer
The time, in seconds, it took from the start until the first byte was just about to be transferred. This
includes time_pretransfer and also the time the server needed to calculate the result.
time_total The total time, in seconds, that the full operation lasted. The time will be displayed with millisecond resolu‐
tion.
url_effective The URL that was fetched last. This is most meaningful if you've told curl to follow location: headers.
If this option is used several times, the last one will be used.
--xattr
When saving output to a file, this option tells curl to store certain file metadata in extended file attributes. Currently, the
URL is stored in the xdg.origin.url attribute and, for HTTP, the content type is stored in the mime_type attribute. If the file
system does not support extended attributes, a warning is issued.
