curl



curl(1)                           Curl Manual                          curl(1)


NAME

       curl - transfer a URL


SYNOPSIS

       curl [options] [URL...]


DESCRIPTION

       curl is a tool to transfer data from or to a server, using one of the
       supported protocols (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP,
       IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMB, SMBS,
       SMTP, SMTPS, TELNET and TFTP). The command is designed to work without
       user interaction.

       curl offers a busload of useful tricks like proxy support, user
       authentication, FTP upload, HTTP post, SSL connections, cookies, file
       transfer resume, Metalink, and more. As you will see below, the number
       of features will make your head spin!

       curl is powered by libcurl for all transfer-related features. See
       libcurl(3) for details.


URL

       The URL syntax is protocol-dependent. You'll find a detailed
       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.numericals.com/file[1-100].txt

         ftp://ftp.numericals.com/file[001-100].txt    (with leading zeros)

         ftp://ftp.letters.com/file[a-z].txt

       Nested sequences are not supported, but you can use several ones next
       to each other:

         http://any.org/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://www.numericals.com/file[1-100:10].txt

         http://www.letters.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 multiple
       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.

       curl displays this data to the terminal by default, so if you invoke
       curl to do an operation and it is about to write data to the terminal,
       it disables the progress meter as otherwise it would mess up the output
       mixing progress meter and response data.

       If you want a progress meter for HTTP POST or PUT requests, you need to
       redirect the response output to a file, using shell redirect (>), -o
       [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, -# is your
       friend.


OPTIONS

       Options start with one or two dashes. Many of the options require an
       additional value next to them.

       The short "single-dash" form of the options, -d for example, may be
       used with or without a space between it and its value, although a space
       is a recommended separator. The long "double-dash" form, --data for
       example, requires a space between it and its value.

       Short version options that don't need any additional values can be used
       immediately next to each other, like for example you can specify all
       the options -O, -L and -v at once as -OLv.

       In general, all boolean options are enabled with --option and yet again
       disabled with --no-option. That is, you use the exact same option name
       but prefix it with "no-". However, in this list we mostly only list and
       show the --option version of them. (This concept with --no options was
       added in 7.19.0. Previously most options were toggled on/off on
       repeated use of the same command line option.)

       -#, --progress-bar
              Make curl display progress as a simple progress bar instead of
              the standard, more informational, meter.

       -:, --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. (Added
              in 7.36.0)

       -0, --http1.0
              (HTTP) Tells curl to use HTTP version 1.0 instead of using its
              internally preferred: HTTP 1.1.

       --http1.1
              (HTTP) Tells curl to use HTTP version 1.1. This is the internal
              default version. (Added in 7.33.0)

       --http2
              (HTTP) Tells curl to issue its requests using HTTP 2. This
              requires that the underlying libcurl was built to support it.
              (Added in 7.33.0)

       --no-npn
              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.

              (Added in 7.36.0)

       --no-alpn
              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.

              (Added in 7.36.0)

       -1, --tlsv1
              (SSL) Forces curl to use TLS version 1.x when negotiating with a
              remote TLS server.  You can use options --tlsv1.0, --tlsv1.1,
              and --tlsv1.2 to control the TLS version more precisely (if the
              SSL backend in use supports such a level of control).

       -2, --sslv2
              (SSL) Forces curl to use SSL version 2 when negotiating with a
              remote SSL server. Sometimes curl is built without SSLv2
              support. SSLv2 is widely considered insecure (see RFC 6176).

       -3, --sslv3
              (SSL) Forces curl to use SSL version 3 when negotiating with a
              remote SSL server. Sometimes curl is built without SSLv3
              support. SSLv3 is widely considered insecure (see RFC 7568).

       -4, --ipv4
              This option tells curl to resolve names to IPv4 addresses only,
              and not for example try IPv6.

       -6, --ipv6
              This option tells curl to resolve names to IPv6 addresses only,
              and not for example try IPv4.

       -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).

       -A, --user-agent <agent string>
              (HTTP) Specify the User-Agent string to send to the HTTP server.
              Some badly done CGIs fail if this field isn't set to
              "Mozilla/4.0". To encode blanks in the string, surround the
              string with single quote marks. This can also be set with the
              -H, --header option of course.

              If this option is used several times, the last one will be used.

       --anyauth
              (HTTP) Tells curl to figure out authentication method by itself,
              and use the most secure one the remote site claims to support.
              This is done by first doing a request and checking the response-
              headers, thus possibly inducing an extra network round-trip.
              This is used instead of setting a specific authentication
              method, which you can do with --basic, --digest, --ntlm, and
              --negotiate.

              Note that 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.

       -b, --cookie <name=data>
              (HTTP) Pass the data to the HTTP server as a cookie. 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 line, it is treated as a
              filename to use to read previously stored cookie lines from,
              which should be used in this session if they match. Using this
              method also activates the cookie engine which will make curl
              record incoming cookies too, which may be handy if you're using
              this in combination with the -L, --location option. The file
              format of the file to read cookies from should be plain HTTP
              headers 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.

       -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.

       --basic
              (HTTP) Tells curl to use HTTP Basic authentication with the
              remote host. This is the default and this option is usually
              pointless, unless you use it to override a previously set option
              that sets a different authentication method (such as --ntlm,
              --digest, or --negotiate).

              Used together with -u, --user and -x, --proxy.

              See also --proxy-basic.

       -c, --cookie-jar <file name>
              (HTTP) Specify to which file you want curl to write all cookies
              after a completed operation. Curl writes all cookies previously
              read from a specified file as well as all cookies received from
              remote server(s). 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
              will get a warning displayed, but that is the only visible
              feedback you get about this possibly lethal situation.

              Since 7.43.0 cookies that were imported in the Set-Cookie format
              without a domain name are not exported by this option.

              If this option is used several times, the last specified file
              name will be used.

       -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.

       --ciphers <list of ciphers>
              (SSL) 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.

       --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.

              See also the -m, --max-time option.

              If this option is used several times, the last one will be used.

       --create-dirs
              When used in conjunction with the -o option, curl will create
              the necessary local directory hierarchy as needed. This option
              creates the dirs mentioned with the -o option, nothing else. If
              the -o 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 Convert LF to CRLF in upload. Useful for MVS (OS/390).

              (SMTP added in 7.40.0)

       --crlfile <file>
              (HTTPS/FTPS) Provide a file using PEM format with a Certificate
              Revocation List that may specify peer certificates that are to
              be considered revoked.

              If this option is used several times, the last one will be used.

              (Added in 7.19.7)

       -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.

              -d, --data is the same as --data-ascii. --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 'foobar' would thus be done with
              --data @foobar. When --data is told to read 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.

       -D, --dump-header <file>
              Write the 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.

       --data-ascii <data>
              See -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 --data-ascii
              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 --data but without the
              special interpretation of the @ character. See -d, --data.
              (Added in 7.43.0)

       --data-urlencode <data>
              (HTTP) This posts data, similar to the other --data options with
              the exception that this performs URL-encoding. (Added in 7.18.0)

              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.

       --delegation LEVEL
              Set LEVEL to tell the server what it is allowed to delegate when
              it comes to user credentials. Used with GSS/kerberos.

              none   Don't allow any delegation.

              policy Delegates if and only if the OK-AS-DELEGATE flag is set
                     in the Kerberos service ticket, which is a matter of
                     realm policy.

              always Unconditionally allow the server to delegate.

       --digest
              (HTTP) Enables HTTP Digest authentication. This is an
              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. See also
              --ntlm, --negotiate and --anyauth for related options.

              If this option is used several times, only the first one is
              used.

       --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.

              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) 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.

              Disabling EPSV only changes the passive behavior. If you want to
              switch to active mode you need to use -P, --ftp-port.

       --dns-interface <interface>
              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).

              This option requires that libcurl was built with a resolver
              backend that supports this operation. The c-ares backend is the
              only such one. (Added in 7.33.0)

       --dns-ipv4-addr <ip-address>
              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.

              This option requires that libcurl was built with a resolver
              backend that supports this operation. The c-ares backend is the
              only such one.  (Added in 7.33.0)

       --dns-ipv6-addr <ip-address>
              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.

              This option requires that libcurl was built with a resolver
              backend that supports this operation. The c-ares backend is the
              only such one.  (Added in 7.33.0)

       --dns-servers <ip-address,ip-address>
              Set the list of DNS servers to be used instead of the system
              default.  The list of IP addresses should be separated with
              commas. Port numbers may also optionally be given as :<port-
              number> after each IP address.

              This option requires that libcurl was built with a resolver
              backend that supports this operation. The c-ares backend is the
              only such one.  (Added in 7.33.0)

       -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 --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 --referer.

              If this option is used several times, the last one will be used.

       -E, --cert <certificate[:password]>
              (SSL) Tells curl to use the specified client certificate file
              when getting a file with HTTPS, FTPS or another SSL-based
              protocol. 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 --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
              (libnsspem.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 Mac OS X only) If curl is built against Secure
              Transport, then the certificate string can either be the name of
              a certificate/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.

       --engine <name>
              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
              (RISC OS ONLY) Sets a range of environment variables, using the
              names the -w option supports, to allow easier extraction of
              useful information after having run curl.

       --egd-file <file>
              (SSL) Specify the path name to the Entropy Gathering Daemon
              socket. The socket is used to seed the random engine for SSL
              connections. See also the --random-file option.

       --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.

              (Added in 7.47.0)

       --cert-type <type>
              (SSL) Tells curl what certificate type the provided certificate
              is in. PEM, DER and ENG are recognized types.  If not specified,
              PEM is assumed.

              If this option is used several times, the last one will be used.

       --cacert <CA certificate>
              (SSL) 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
              directory 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.

              If this option is used several times, the last one will be used.

       --capath <CA certificate directory>
              (SSL) 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.

       --pinnedpubkey <pinned public key (hashes)>
              (SSL) Tells curl to use the specified public key file (or
              hashes) to verify the peer. This can be a path to a file which
              contains a single public key in PEM or DER format, or any number
              of base64 encoded sha256 hashes preceded by 'sha256//' and
              separated by ';'

              When negotiating a TLS or SSL connection, the server sends a
              certificate indicating its identity. A public key is extracted
              from this certificate and if it does not exactly match the
              public key provided to this option, curl will abort the
              connection before sending or receiving any data.

              Added in 7.39.0 for OpenSSL, GnuTLS and GSKit. Added in 7.43.0
              for NSS and wolfSSL/CyaSSL. sha256 support added in 7.44.0 for
              OpenSSL, GnuTLS, NSS and wolfSSL/CyaSSL. Other SSL backends not
              supported.

              If this option is used several times, the last one will be used.

       --cert-status
              (SSL) 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)

       --false-start

              (SSL) 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)

       -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).

       -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 your password file to the server, where
              'password' is the name of the form-field to which /etc/passwd
              will be the input:

              curl -F password=@/etc/passwd www.mypasswords.com

              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" url.com

              or

              curl -F "name=daniel;type=text/foo" url.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" url.com

              If filename/path contains ',' or ';', it must be quoted by
              double-quotes like:

              curl -F "file=@\"localfile\";filename=\"nameinpost\"" url.com

              or

              curl -F 'file=@"localfile";filename="nameinpost"' url.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.

       --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. (Added in 7.13.0)

              If this option is used several times, the last one will be used.

       --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.

       --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
              following alternatives:

              multicwd
                     curl does a single CWD operation for each path part in
                     the given URL. For deep hierarchies this means very many
                     commands. This is how RFC 1738 says it should be done.
                     This is the default but the slowest behavior.

              nocwd  curl does no CWD at all. curl will do SIZE, RETR, STOR
                     etc and give a full path to the server for all these
                     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. (Added in 7.11.0)

              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.

       --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. (Added in 7.14.2)

              This option has no effect if PORT, EPRT or EPSV is used instead
              of PASV.

       --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.x)

       --ftp-ssl-ccc
              (FTP) Use CCC (Clear Command Channel) Shuts down the SSL/TLS
              layer after authenticating. The rest of the control channel
              communication will be unencrypted. This allows NAT routers to
              follow the FTP transaction. The default mode is passive. See
              --ftp-ssl-ccc-mode for other modes.  (Added in 7.16.1)

       --ftp-ssl-ccc-mode [active/passive]
              (FTP) Use CCC (Clear Command Channel) 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.  (Added in 7.16.2)

       --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) that can still be used but
              will be removed in a future version.

       --form-string <name=string>
              (HTTP) Similar to --form except that the value string for the
              named parameter is used literally. Leading '@' and '<'
              characters, and the ';type=' string in the value have no special
              meaning. Use this in preference to --form if there's any
              possibility that the string value may accidentally trigger the
              '@' or '<' features of --form.

       -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.

       -G, --get
              When used, this option will make all data specified with -d,
              --data, --data-binary or --data-urlencode to be used in an HTTP
              GET request instead of the POST request that otherwise would be
              used. The data will be appended to the URL with a '?' separator.

              If used in combination with -I, 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.

       -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://192.168.0.1/

              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.

       --hostpubmd5 <md5>
              (SCP/SFTP) 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)

       --ignore-content-length
              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
              (HTTP) Include the HTTP-header in the output. The HTTP-header
              includes things like server-name, date of the document, HTTP-
              version and more...

       -I, --head
              (HTTP/FTP/FILE) Fetch the HTTP-header 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.

       --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 http://www.netscape.com/

              If this option is used several times, the last one will be used.

       -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.

       -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.

              There's no attempt to decode %-sequences (yet) in the provided
              file name, so this option may provide you with rather unexpected
              file names.

       -k, --insecure
              (SSL) 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:
              http://curl.haxx.se/docs/sslcerts.html

       -K, --config <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
              column of a config line is a '#' character, the rest of the line
              will be treated as a comment. Only write one option per physical
              line in the config file.

              Specify the filename to -K, --config as '-' to make curl read
              the file from stdin.

              Note that to be able to specify a URL in the config file, you
              need to specify it using the --url option, and not by simply
              writing the URL on its own line. So, it could look similar to
              this:

              url = "http://curl.haxx.se/docs/"

              When curl is invoked, it always (unless -q 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 = "curl.haxx.se"
              output = "curlhere.html"
              user-agent = "superagent/1.0"

              # and fetch another URL too
              url = "curl.haxx.se/docs/manpage.html"
              -O
              referer = "http://nowhereatall.com/"
              # --- End of example file ---

              This option can be used multiple times to load multiple config
              files.

       --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. (Added in 7.18.0)

              If this option is used several times, the last one will be used.
              If unspecified, the option defaults to 60 seconds.

       --key <key>
              (SSL/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: '~/.ssh/id_rsa',
              '~/.ssh/id_dsa', './id_rsa', './id_dsa'.

              If this option is used several times, the last one will be used.

       --key-type <type>
              (SSL) 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.

       --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.

              This option requires a library built with kerberos4 support.
              This is not very common. Use -V, --version to see if your curl
              supports it.

              If this option is used several times, the last one will be used.

       -l, --list-only
              (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 <command>, 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)

       -L, --location
              (HTTP/HTTPS) 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
              --location-trusted on how to change this. You can limit the
              amount of redirects to follow by using the --max-redirs option.

              When curl follows a redirect and the request is not a plain GET
              (for example POST or PUT), it will do the following request with
              a GET if the HTTP response was 301, 302, or 303. If the response
              code was any other 3xx code, curl will re-send the following
              request using the same unmodified method.

              You can tell curl to not change the non-GET request method to
              GET after a 30x response by using the dedicated options for
              that: --post301, --post302 and -post303.

       --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
              kilobytes, 'm' or M' makes it megabytes, while 'g' or 'G' makes
              it gigabytes. Examples: 200K, 3m and 1G.

              The given rate is the average speed counted during the entire
              transfer. It means that curl might use higher transfer speeds in
              short bursts, but over time it uses no more than the given rate.

              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.

       --local-port <num>[-num]
              Set a preferred number or range 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/HTTPS) 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).

       -m, --max-time <seconds>
              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.  See also the --connect-timeout
              option.

              If this option is used several times, the last one will be used.

       --login-options <options>
              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 (Added in 7.34.0).

              If this option is used several times, the last one will be used.

       --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.

              (Added in 7.25.0)

       --mail-from <address>
              (SMTP) Specify a single address that the given mail should get
              sent from.

              (Added in 7.20.0)

       --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
              transfer ends up being larger than this given limit. This
              concerns both FTP and HTTP transfers.

       --mail-rcpt <address>
              (SMTP) Specify a single address, user name or mailing list name.

              When performing a mail transfer, the recipient should specify a
              valid email address to send the mail to. (Added in 7.20.0)

              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)

       --max-redirs <num>
              Set maximum number of redirection-followings allowed. If -L,
              --location is used, this option can be used to prevent curl from
              following redirections "in absurdum". By default, the limit is
              set to 50 redirections. Set this option to -1 to make it
              limitless.

              If this option is used several times, the last one will be used.

       --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 --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.

              (Added in 7.27.0, if built against the libmetalink library.)

       -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 format. 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

       -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.

       --netrc-file
              This option is similar to --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, only the last one
              will be used.  (Added in 7.21.5)

              This option overrides any use of --netrc as they are mutually
              exclusive.  It will also abide by --netrc-optional if specified.

       --netrc-optional
              Very similar to --netrc, but this option makes the .netrc usage
              optional and not mandatory as the --netrc option does.

       --negotiate
              (HTTP) Enables Negotiate (SPNEGO) authentication.

              If you want to enable Negotiate (SPNEGO) for proxy
              authentication, then use --proxy-negotiate.

              This option requires a library built with GSS-API or SSPI
              support. Use -V, --version to see if your curl supports GSS-
              API/SSPI and 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
              option aren't actually used.

              If this option is used several times, only the first one is
              used.

       --no-keepalive
              Disables the use of keepalive messages on the TCP connection, as
              by default curl enables them.

              Note that this is the negated option name documented. You can
              thus use --keepalive to enforce keepalive.

       --no-sessionid
              (SSL) 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. (Added
              in 7.16.0)

              Note that this is the negated option name documented. You can
              thus use --sessionid to enforce session-ID caching.

       --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 (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
              authentication method instead, such as Digest.

              If you want to enable NTLM for your proxy authentication, then
              use --proxy-ntlm.

              This option requires a library built with SSL support. Use -V,
              --version to see if your curl supports NTLM.

              If this option is used several times, only the first one is
              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}.site.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.

              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.

       -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 remote file name to use for saving is extracted from the
              given URL, nothing else.

              Consequentially, the file will be saved in the current working
              directory. If you want the file saved in a different directory,
              make sure you change current working directory before you invoke
              curl with the -O, --remote-name flag!

              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.

       --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.

       --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)

       -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.

       -P, --ftp-port <address>
              (FTP) Reverses the default initiator/listener roles when
              connecting with FTP. This switch makes curl use active mode. In
              practice, 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++.

              Starting in 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 failure since the port may not be available.

       --pass <phrase>
              (SSL/SSH) 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)

       --post301
              (HTTP) Tells curl to respect RFC 7230/6.4.2 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 (Added in 7.17.1)

       --post302
              (HTTP) Tells curl to respect RFC 7230/6.4.3 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 (Added in 7.19.1)

       --post303
              (HTTP) Tells curl to respect RFC 7230/6.4.4 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 (Added in 7.26.0)

       --proto <protocols>
              Tells curl to use the listed protocols for its initial
              retrieval. Protocols are evaluated left to right, are comma
              separated, and are each a protocol name or 'all', optionally
              prefixed by zero or more modifiers. Available modifiers are:

              +  Permit this protocol in addition to protocols already
                 permitted (this is the default if no modifier is used).

              -  Deny this protocol, removing it from the list of 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.

              (Added in 7.20.2)

       --proto-default <protocol>
              Tells curl to use protocol for any URL missing a scheme name.

              Example:

              --proto-default https ftp.mozilla.org
                     https://ftp.mozilla.org

       An unknown or unsupported protocol causes error
       CURLE_UNSUPPORTED_PROTOCOL.

       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 use the listed protocols on redirect. See --proto
              for how protocols are represented.

              Example:

              --proto-redir -all,http,https
                     Allow only HTTP and HTTPS on redirect.

       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)

       --proxy-anyauth
              Tells curl to pick a suitable authentication method when
              communicating with the given proxy. This might cause an extra
              request/response round-trip. (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.

       --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.

       --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. (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.

       --proxy-service-name <servicename>
              This option allows you to change the service name for proxy
              negotiation.

              Examples: --proxy-negotiate proxy-name --proxy-service-name
              sockd would use sockd/proxy-name.  (Added in 7.43.0).

       --proxy1.0 <proxyhost[: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.

       --pubkey <key>
              (SSH) 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
              generally 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     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.

       -Q, --quote <command>
              (FTP/SFTP) Send an arbitrary command to the remote FTP or SFTP
              server. Quote commands are sent BEFORE the transfer takes place
              (just after the initial PWD command in an FTP transfer, to be
              exact). To make commands take place after a successful transfer,
              prefix them with a dash '-'.  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 correct
              FTP commands as RFC 959 defines to FTP servers, or one of the
              commands listed below to SFTP servers.  This option can be used
              multiple times. When speaking to an FTP server, prefix the
              command with an asterisk (*) to make curl continue even if the
              command fails as by default curl will stop at first failure.

              SFTP is a binary protocol. Unlike for FTP, curl interprets SFTP
              quote commands itself before sending them to the server.  File
              names may be quoted shell-style to embed spaces or special
              characters.  Following is the list of all supported SFTP quote
              commands:

              chgrp group file
                     The chgrp command sets the group ID of the file named by
                     the file operand to the group ID specified by the group
                     operand. The group operand is a decimal integer group ID.

              chmod mode file
                     The chmod command modifies the file mode bits of the
                     specified file. The mode operand is an octal integer mode
                     number.

              chown user file
                     The chown command sets the owner of the file named by the
                     file operand to the user ID specified by the user
                     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.

       -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
              character 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.

       -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.

       --random-file <file>
              (SSL) Specify the path name to file containing what will be
              considered as random data. The data is used to seed the random
              engine for SSL connections.  See also the --egd-file option.

       --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)

       --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)

       --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.

              This option can be used many times to add many host names to
              resolve.

              (Added in 7.21.3)

       --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.
              (Added in 7.12.3)

              If this option is used several times, the last one will be used.

       --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.  (Added in
              7.12.3)

              If this option is used several times, the last one will be used.

       --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
              performing, it may take longer than this given time period. To
              limit a single request's maximum time, use -m, --max-time.  Set
              this option to zero to not timeout retries. (Added in 7.12.3)

              If this option is used several times, the last one will be used.

       -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.

       --sasl-ir
              Enable initial response in SASL authentication.  (Added in
              7.31.0)

       --service-name <servicename>
              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 it makes curl show an error message if it
              fails.

       --ssl  (FTP, POP3, IMAP, 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. (Added in 7.20.0)

              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.

       --ssl-reqd
              (FTP, POP3, IMAP, SMTP) Require SSL/TLS for the connection.
              Terminates the connection if the server doesn't support SSL/TLS.
              (Added in 7.20.0)

              This option was formerly known as --ftp-ssl-reqd (added in
              7.15.5). That option name can still be used but will be removed
              in a future version.

       --ssl-allow-beast
              (SSL) 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)

       --socks4 <host[:port]>
              Use the specified SOCKS4 proxy. If the port number is not
              specified, it is assumed at port 1080. (Added in 7.15.2)

              This option overrides any previous use of -x, --proxy, as they
              are mutually exclusive.

              Since 7.21.7, this option is superfluous since you can specify a
              socks4 proxy with -x, --proxy using a socks4:// protocol prefix.

              If this option is used several times, the last one will be used.

       --socks4a <host[:port]>
              Use the specified SOCKS4a proxy. If the port number is not
              specified, it is assumed at port 1080. (Added in 7.18.0)

              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.

       --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. (Added in 7.18.0)

              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://
              protocol prefix.

              If this option is used several times, the last one will be used.
              (This option was previously wrongly documented and used as
              --socks without the number appended.)

       --socks5 <host[:port]>
              Use the specified SOCKS5 proxy - but resolve the host name
              locally. If the port number is not specified, it is assumed at
              port 1080.

              This option overrides any previous use of -x, --proxy, as they
              are mutually exclusive.

              Since 7.21.7, this option is superfluous since you can specify a
              socks5 proxy with -x, --proxy using a socks5:// protocol prefix.

              If this option is used several times, the last one will be used.
              (This option was previously wrongly documented and used as
              --socks without the number appended.)

              This option (as well as --socks4) does not work with IPV6, FTPS
              or LDAP.

       --socks5-gssapi-service <servicename>
              The default service name for a socks server is rcmd/server-fqdn.
              This option allows you to change it.

              Examples: --socks5 proxy-name --socks5-gssapi-service sockd
              would use sockd/proxy-name --socks5 proxy-name --socks5-gssapi-
              service sockd/real-name would use sockd/real-name for cases
              where the proxy-name does not match the principal name.  (Added
              in 7.19.4).

       --socks5-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 protection mode negotiation. (Added in 7.19.4).

       --stderr <file>
              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.

       -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.

       -T, --upload-file <file>
              This transfers the specified local file to the remote URL. If
              there is no file part in the specified URL, Curl will append the
              local file name. NOTE that you must use a trailing / on the last
              directory to really prove to Curl that there is no file name or
              curl will think that your last directory name is the remote file
              name to use. That will most likely cause the upload operation to
              fail. If this is used on an HTTP(S) server, the PUT command will
              be used.

              Use the file name "-" (a single dash) to use stdin instead of a
              given file.  Alternately, the file name "." (a single period)
              may be specified instead of "-" to use stdin in non-blocking
              mode to allow reading server output while stdin is being
              uploaded.

              You can specify one -T for each URL on the command line. Each -T
              + URL pair specifies what to upload and to where. curl also
              supports "globbing" of the -T 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 -T "{file1,file2}" http://www.uploadtothissite.com

              or even

              curl -T "img[1-1000].png" ftp://ftp.picturemania.com/upload/

       --tcp-nodelay
              Turn on the TCP_NODELAY option. See the curl_easy_setopt(3) man
              page for details about this option. (Added in 7.11.2)

       --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)

       --tlsauthtype <authtype>
              Set TLS authentication type. Currently, the only supported
              option is "SRP", for TLS-SRP (RFC 5054). If --tlsuser and
              --tlspassword are specified but --tlsauthtype is not, then this
              option defaults to "SRP".  (Added in 7.21.4)

       --tlspassword <password>
              Set password for use with the TLS authentication method
              specified with --tlsauthtype. Requires that --tlsuser also be
              set.  (Added in 7.21.4)

       --tlsuser <user>
              Set username for use with the TLS authentication method
              specified with --tlsauthtype. Requires that --tlspassword also
              be set.  (Added in 7.21.4)

       --tlsv1.0
              (SSL) Forces curl to use TLS version 1.0 when negotiating with a
              remote TLS server.  (Added in 7.34.0)

       --tlsv1.1
              (SSL) Forces curl to use TLS version 1.1 when negotiating with a
              remote TLS server.  (Added in 7.34.0)

       --tlsv1.2
              (SSL) Forces curl to use TLS version 1.2 when negotiating with a
              remote TLS server.  (Added in 7.34.0)

       --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 <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 option overrides previous uses of -v, --verbose or --trace-
              ascii.

              If this option is used several times, the last one will be used.

       --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.

              This option overrides previous uses of -v, --verbose or --trace.

              If this option is used several times, the last one will be used.

       --trace-time
              Prepends a time stamp to each trace or verbose line that curl
              displays.  (Added in 7.14.0)

       --unix-socket <path>
              (HTTP) Connect through this Unix domain socket, instead of using
              the network. (Added in 7.40.0)

       -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.

       -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.

       --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.

       -v, --verbose
              Be more verbose/talkative 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.

              Note that 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.

              This option overrides previous uses of --trace-ascii or --trace.

              Use -s, --silent to make curl quiet.

       -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 --remote-name or --output
                             option. It's most useful in combination with the
                             --remote-header-name option. (Added in 7.25.1)

              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)

              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)

              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 completed. (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 redirections. (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 resolution.

              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.

       -x, --proxy <[protocol://][user:password@]proxyhost[: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
              characters 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.

       -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 explanations. 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
              command 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 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.

       --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.

       -y, --speed-time <time>
              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.

              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.

       -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 and is 30 if not set.

              If this option is used several times, the last one will be used.

       -z, --time-cond <date expression>|<file>
              (HTTP/FTP) Request a file that has been modified later than the
              given time and date, or one that has been modified before that
              time. The <date expression> can be all sorts of date strings or
              if it doesn't match any internal ones, it is taken as a filename
              and tries to get the modification date (mtime) from <file>
              instead. See the curl_getdate(3) man pages for date expression
              details.

              Start the date expression with a dash (-) to make it request for
              a document that is older than the given date/time, default is a
              document that is newer than the specified date/time.

              If this option is used several times, the last one will be used.

       -h, --help
              Usage help. This lists all current command line options with a
              short description.

       -M, --manual
              Manual. Display the huge help text.

       -V, --version
              Displays information about curl and the libcurl version it uses.

              The first line includes the full version of curl, libcurl and
              other 3rd party libraries linked with the executable.

              The second line (starts with "Protocols:") shows all protocols
              that libcurl reports to support.

              The third line (starts with "Features:") shows specific features
              libcurl reports to offer. Available features include:

              IPv6   You can use IPv6 with this.

              krb4   Krb4 for FTP is supported.

              SSL    SSL versions of various protocols are supported, such as
                     HTTPS, FTPS, POP3S and so on.

              libz   Automatic decompression of compressed files over HTTP is
                     supported.

              NTLM   NTLM authentication is supported.

              Debug  This curl uses a libcurl built with Debug. This enables
                     more error-tracking and memory debugging etc. For curl-
                     developers only!

              AsynchDNS
                     This curl uses asynchronous name resolves. Asynchronous
                     name resolves can be done using either the c-ares or the
                     threaded resolver backends.

              SPNEGO SPNEGO authentication is supported.

              Largefile
                     This curl supports transfers of large files, files larger
                     than 2GB.

              IDN    This curl supports IDN - international domain names.

              GSS-API
                     GSS-API is supported.

              SSPI   SSPI is supported.

              TLS-SRP
                     SRP (Secure Remote Password) authentication is supported
                     for TLS.

              HTTP2  HTTP/2 support has been built-in.

              Metalink
                     This curl supports Metalink (both version 3 and 4 (RFC
                     5854)), which describes mirrors and hashes.  curl will
                     use mirrors for failover if there are errors (such as the
                     file or server not being available).


FILES

       ~/.curlrc
              Default config file, see -K, --config for details.


ENVIRONMENT

       The environment variables can be specified in lower case or upper case.
       The lower case version has precedence. http_proxy is an exception as it
       is only available in lower case.

       Using an environment variable to set the proxy has the same effect as
       using the --proxy option.

       http_proxy [protocol://]<host>[:port]
              Sets the proxy server to use for HTTP.

       HTTPS_PROXY [protocol://]<host>[:port]
              Sets the proxy server to use for HTTPS.

       [url-protocol]_PROXY [protocol://]<host>[:port]
              Sets the proxy server to use for [url-protocol], where the
              protocol is a protocol that curl supports and as specified in a
              URL. FTP, FTPS, POP3, IMAP, SMTP, LDAP etc.

       ALL_PROXY [protocol://]<host>[:port]
              Sets the proxy server to use if no protocol-specific proxy is
              set.

       NO_PROXY <comma-separated list of hosts>
              list of host names that shouldn't go through any proxy. If set
              to a asterisk '*' only, it matches all hosts.


PROXY PROTOCOL PREFIXES

       Since curl version 7.21.7, the proxy string may be specified with a
       protocol:// prefix to specify alternative proxy protocols.

       If no protocol is specified in the proxy string or if the string
       doesn't match a supported one, the proxy will be treated as an HTTP
       proxy.

       The supported proxy protocol prefixes are as follows:

       socks4://
              Makes it the equivalent of --socks4

       socks4a://
              Makes it the equivalent of --socks4a

       socks5://
              Makes it the equivalent of --socks5

       socks5h://
              Makes it the equivalent of --socks5-hostname


EXIT CODES

       There are a bunch of different error codes and their corresponding
       error messages that may appear during bad conditions. At the time of
       this writing, the exit codes are:

       1      Unsupported protocol. This build of curl has no support for this
              protocol.

       2      Failed to initialize.

       3      URL malformed. The syntax was not correct.

       4      A feature or option that was needed to perform the desired
              request was not enabled or was explicitly disabled at build-
              time. To make curl able to do this, you probably need another
              build of libcurl!

       5      Couldn't resolve proxy. The given proxy host could not be
              resolved.

       6      Couldn't resolve host. The given remote host was not resolved.

       7      Failed to connect to host.

       8      FTP weird server reply. The server sent data curl couldn't
              parse.

       9      FTP access denied. The server denied login or denied access to
              the particular resource or directory you wanted to reach. Most
              often you tried to change to a directory that doesn't exist on
              the server.

       11     FTP weird PASS reply. Curl couldn't parse the reply sent to the
              PASS request.

       13     FTP weird PASV reply, Curl couldn't parse the reply sent to the
              PASV request.

       14     FTP weird 227 format. Curl couldn't parse the 227-line the
              server sent.

       15     FTP can't get host. Couldn't resolve the host IP we got in the
              227-line.

       17     FTP couldn't set binary. Couldn't change transfer method to
              binary.

       18     Partial file. Only a part of the file was transferred.

       19     FTP couldn't download/access the given file, the RETR (or
              similar) command failed.

       21     FTP quote error. A quote command returned error from the server.

       22     HTTP page not retrieved. The requested url was not found or
              returned another error with the HTTP error code being 400 or
              above. This return code only appears if -f, --fail is used.

       23     Write error. Curl couldn't write data to a local filesystem or
              similar.

       25     FTP couldn't STOR file. The server denied the STOR operation,
              used for FTP uploading.

       26     Read error. Various reading problems.

       27     Out of memory. A memory allocation request failed.

       28     Operation timeout. The specified time-out period was reached
              according to the conditions.

       30     FTP PORT failed. The PORT command failed. Not all FTP servers
              support the PORT command, try doing a transfer using PASV
              instead!

       31     FTP couldn't use REST. The REST command failed. This command is
              used for resumed FTP transfers.

       33     HTTP range error. The range "command" didn't work.

       34     HTTP post error. Internal post-request generation error.

       35     SSL connect error. The SSL handshaking failed.

       36     FTP bad download resume. Couldn't continue an earlier aborted
              download.

       37     FILE couldn't read file. Failed to open the file. Permissions?

       38     LDAP cannot bind. LDAP bind operation failed.

       39     LDAP search failed.

       41     Function not found. A required LDAP function was not found.

       42     Aborted by callback. An application told curl to abort the
              operation.

       43     Internal error. A function was called with a bad parameter.

       45     Interface error. A specified outgoing interface could not be
              used.

       47     Too many redirects. When following redirects, curl hit the
              maximum amount.

       48     Unknown option specified to libcurl. This indicates that you
              passed a weird option to curl that was passed on to libcurl and
              rejected. Read up in the manual!

       49     Malformed telnet option.

       51     The peer's SSL certificate or SSH MD5 fingerprint was not OK.

       52     The server didn't reply anything, which here is considered an
              error.

       53     SSL crypto engine not found.

       54     Cannot set SSL crypto engine as default.

       55     Failed sending network data.

       56     Failure in receiving network data.

       58     Problem with the local certificate.

       59     Couldn't use specified SSL cipher.

       60     Peer certificate cannot be authenticated with known CA
              certificates.

       61     Unrecognized transfer encoding.

       62     Invalid LDAP URL.

       63     Maximum file size exceeded.

       64     Requested FTP SSL level failed.

       65     Sending the data requires a rewind that failed.

       66     Failed to initialise SSL Engine.

       67     The user name, password, or similar was not accepted and curl
              failed to log in.

       68     File not found on TFTP server.

       69     Permission problem on TFTP server.

       70     Out of disk space on TFTP server.

       71     Illegal TFTP operation.

       72     Unknown TFTP transfer ID.

       73     File already exists (TFTP).

       74     No such user (TFTP).

       75     Character conversion failed.

       76     Character conversion functions required.

       77     Problem with reading the SSL CA cert (path? access rights?).

       78     The resource referenced in the URL does not exist.

       79     An unspecified error occurred during the SSH session.

       80     Failed to shut down the SSL connection.

       82     Could not load CRL file, missing or wrong format (added in
              7.19.0).

       83     Issuer check failed (added in 7.19.0).

       84     The FTP PRET command failed

       85     RTSP: mismatch of CSeq numbers

       86     RTSP: mismatch of Session Identifiers

       87     unable to parse FTP file list

       88     FTP chunk callback reported error

       89     No connection available, the session will be queued

       90     SSL public key does not matched pinned public key

       XX     More error codes will appear here in future releases. The
              existing ones are meant to never change.


AUTHORS / CONTRIBUTORS

       Daniel Stenberg is the main author, but the whole list of contributors
       is found in the separate THANKS file.


WWW

       http://curl.haxx.se


FTP

       ftp://ftp.sunet.se/pub/www/utilities/curl/


SEE ALSO

       ftp(1), wget(1)

Curl 7.40.0                       30 Nov 2014                          curl(1)

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