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 curl(1)                         Curl 7.52.0                         curl(1)
 Curl Manual                                                     Curl Manual

                                 16 Dec 2016



 NAME
      curl - transfer a URL

 SYNOPSIS
      curl [options / URLs]

 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, MQTT, POP3, POP3S, RTMP, RTMPS, 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 and quoting the URL as in:

        "http://site.{one,two,three}.com"

      or you can get sequences of alphanumeric series by using [] as in:

        "ftp://ftp.example.com/file[1-100].txt"

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

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

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

        "http://example.com/archive[1996-1999]/vol[1-4]/part{a,b,c}.html"

      You can specify any amount of URLs on the command line. They will be
      fetched in a sequential manner in the specified order. You can specify
      command line options and URLs mixed and in any order on the command
      line.

      You can specify a step counter for the ranges to get every Nth number



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                                 16 Dec 2016



      or letter:

        "http://example.com/file[1-100:10].txt"

        "http://example.com/file[a-z:2].txt"

      When using [] or {} sequences when invoked from a command line prompt,
      you probably have to put the full URL within double quotes to avoid
      the shell from interfering with it. This also goes for other
      characters treated special, like for example '&', '?' and '*'.

      Provide the IPv6 zone index in the URL with an escaped percentage sign
      and the interface name. Like in

        "http://[fe80::3%25eth0]/"

      If you specify URL without protocol:// prefix, curl will attempt to
      guess what protocol you might want. It will then default to HTTP but
      try other protocols based on often-used host name prefixes. For
      example, for host names starting with "ftp." curl will assume you want
      to speak FTP.

      curl will do its best to use what you pass to it as a URL. It is not
      trying to validate it as a syntactically correct URL by any means but
      is instead very liberal with what it accepts.

      curl will attempt to re-use connections for multiple file transfers,
      so that getting many files from the same server will not do 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. The progress meter displays number of bytes and the speeds
      are in bytes per second. The suffixes (k, M, G, T, P) are 1024 based.
      For example 1k is 1024 bytes. 1M is 1048576 bytes.

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

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

      It is not the same case for FTP upload as that operation does not spit



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      out any response data to the terminal.

      If you prefer a progress "bar" instead of the regular meter, -#, --
      progress-bar is your friend. You can also disable the progress meter
      completely with the -s, --silent option.

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

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

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

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

      --abstract-unix-socket <path>
           (HTTP) Connect through an abstract Unix domain socket, instead of
           using the network.  Note: netstat shows the path of an abstract
           socket prefixed with '@', however the <path> argument should not
           have this leading character.

           Added in 7.53.0.

      --alt-svc <file name>
           (HTTPS) WARNING: this option is experimental. Do not use in
           production.

           This option enables the alt-svc parser in curl. If the file name
           points to an existing alt-svc cache file, that will be used.
           After a completed transfer, the cache will be saved to the file
           name again if it has been modified.

           Specify a "" file name (zero length) to avoid loading/saving and
           make curl just handle the cache in memory.

           If this option is used several times, curl will load contents
           from all the files but the last one will be used for saving.




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 Curl Manual                                                     Curl Manual

                                 16 Dec 2016



           Added in 7.64.1.

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

           Using --anyauth is not recommended if you do uploads from stdin,
           since it may require data to be sent twice and then the client
           must be able to rewind. If the need should arise when uploading
           from stdin, the upload operation will fail.

           Used together with -u, --user.

           See also --proxy-anyauth and --basic and --digest.

      -a, --append
           (FTP SFTP) When used in an upload, this makes curl append to the
           target file instead of overwriting it. If the remote file doesn't
           exist, it will be created.  Note that this flag is ignored by
           some SFTP servers (including OpenSSH).

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

           Used together with -u, --user.

           See also --proxy-basic.

      --cacert <file>
           (TLS) Tells curl to use the specified certificate file to verify
           the peer. The file may contain multiple CA certificates. The
           certificate(s) must be in PEM format. Normally curl is built to
           use a default file for this, so this option is typically used to
           alter that default file.

           curl recognizes the environment variable named 'CURL_CA_BUNDLE'
           if it is set, and uses the given path as a path to a CA cert
           bundle. This option overrides that variable.

           The windows version of curl will automatically look for a CA
           certs file named 'curl-ca-bundle.crt', either in the same



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           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.

           (iOS and macOS only) If curl is built against Secure Transport,
           then this option is supported for backward compatibility with
           other SSL engines, but it should not be set. If the option is not
           set, then curl will use the certificates in the system and user
           Keychain to verify the peer, which is the preferred method of
           verifying the peer's certificate chain.

           (Schannel only) This option is supported for Schannel in Windows
           7 or later with libcurl 7.60 or later. This option is supported
           for backward compatibility with other SSL engines; instead it is
           recommended to use Windows' store of root certificates (the
           default for Schannel).

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

      --capath <dir>
           (TLS) Tells curl to use the specified certificate directory to
           verify the peer. Multiple paths can be provided by separating
           them with ":" (e.g.  "path1:path2:path3"). The certificates must
           be in PEM format, and if curl is built against OpenSSL, the
           directory must have been processed using the c_rehash utility
           supplied with OpenSSL. Using --capath can allow OpenSSL-powered
           curl to make SSL-connections much more efficiently than using --
           cacert if the --cacert file contains many CA certificates.

           If this option is set, the default capath value will be ignored,
           and if it is used several times, the last one will be used.

      --cert-status
           (TLS) Tells curl to verify the status of the server certificate
           by using the Certificate Status Request (aka. OCSP stapling) TLS
           extension.

           If this option is enabled and the server sends an invalid (e.g.
           expired) response, if the response suggests that the server
           certificate has been revoked, or no response at all is received,
           the verification fails.

           This is currently only implemented in the OpenSSL, GnuTLS and NSS
           backends.

           Added in 7.41.0.



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      --cert-type <type>
           (TLS) Tells curl what type the provided client certificate is
           using. PEM, DER, ENG and P12 are recognized types.  If not
           specified, PEM is assumed.

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

           See also -E, --cert and --key and --key-type.

      -E, --cert <certificate[:password]>
           (TLS) Tells curl to use the specified client certificate file
           when getting a file with HTTPS, FTPS or another SSL-based
           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 -E, --cert and --key to specify them independently.

           If curl is built against the NSS SSL library then this option can
           tell curl the nickname of the certificate to use within the NSS
           database defined by the environment variable SSL_DIR (or by
           default /etc/pki/nssdb). If the NSS PEM PKCS#11 module
           (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.

           If curl is built against OpenSSL library, and the engine pkcs11
           is available, then a PKCS#11 URI (RFC 7512) can be used to
           specify a certificate located in a PKCS#11 device. A string
           beginning with "pkcs11:" will be interpreted as a PKCS#11 URI. If
           a PKCS#11 URI is provided, then the --engine option will be set
           as "pkcs11" if none was provided and the --cert-type option will
           be set as "ENG" if none was provided.

           (iOS and macOS 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.

           (Schannel only) Client certificates must be specified by a path
           expression to a certificate store. (Loading PFX is not supported;
           you can import it to a store first). You can use "<store



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           location>\<store name>\<thumbprint>" to refer to a certificate in
           the system certificates store, for example,
           "CurrentUser\MY\934a7ac6f8a5d579285a74fa61e19f23ddfe8d7a".
           Thumbprint is usually a SHA-1 hex string which you can see in
           certificate details. Following store locations are supported:
           CurrentUser, LocalMachine, CurrentService, Services,
           CurrentUserGroupPolicy, LocalMachineGroupPolicy,
           LocalMachineEnterprise.

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

           See also --cert-type and --key and --key-type.

      --ciphers <list of ciphers>
           (TLS) Specifies which ciphers to use in the connection. The list
           of ciphers must specify valid ciphers. Read up on SSL cipher list
           details on this URL:

            https://curl.haxx.se/docs/ssl-ciphers.html

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

      --compressed-ssh
           (SCP SFTP) Enables built-in SSH compression.  This is a request,
           not an order; the server may or may not do it.

           Added in 7.56.0.

      --compressed
           (HTTP) Request a compressed response using one of the algorithms
           curl supports, and automatically decompress the content. Headers
           are not modified.

           If this option is used and the server sends an unsupported
           encoding, curl will report an error.

      -K, --config <file>

           Specify a text file to read curl arguments from. The command line
           arguments found in the text file will be used as if they were
           provided on the command line.

           Options and their parameters must be specified on the same line
           in the file, separated by whitespace, colon, or the equals sign.
           Long option names can optionally be given in the config file
           without the initial double dashes and if so, the colon or equals
           characters can be used as separators. If the option is specified
           with one or two dashes, there can be no colon or equals character
           between the option and its parameter.



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           If the parameter contains whitespace (or starts with : or =), the
           parameter must be enclosed within quotes. Within double quotes,
           the following escape sequences are available: \\, \", \t, \n, \r
           and \v. A backslash preceding any other letter is ignored. If the
           first column of a config line is a '#' character, the rest of the
           line will be treated as a comment. Only write one option per
           physical line in the config file.

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

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

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

           When curl is invoked, it (unless -q, --disable is used) checks
           for a default config file and uses it if found. The default
           config file is checked for in the following places in this order:

           1) curl tries to find the "home dir": It first checks for the
           CURL_HOME and then the HOME environment variables. Failing that,
           it uses getpwuid() on Unix-like systems (which returns the home
           dir given the current user in your system). On Windows, it then
           checks for the APPDATA variable, or as a last resort the
           '%USERPROFILE%\Application Data'.

           2) On windows, if there is no .curlrc file in the home dir, it
           checks for one in the same dir the curl executable is placed. On
           Unix-like systems, it will simply try to load .curlrc from the
           determined home dir.

           # --- Example file ---
           # this is a comment
           url = "example.com"
           output = "curlhere.html"
           user-agent = "superagent/1.0"

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

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




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      --connect-timeout <seconds>
           Maximum time in seconds that you allow curl's connection to take.
           This only limits the connection phase, so if curl connects within
           the given period it will continue - if not it will exit.  Since
           version 7.32.0, this option accepts decimal values.

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

           See also -m, --max-time.

      --connect-to <HOST1:PORT1:HOST2:PORT2>

           For a request to the given HOST1:PORT1 pair, connect to
           HOST2:PORT2 instead.  This option is suitable to direct requests
           at a specific server, e.g. at a specific cluster node in a
           cluster of servers. This option is only used to establish the
           network connection. It does NOT affect the hostname/port that is
           used for TLS/SSL (e.g. SNI, certificate verification) or for the
           application protocols. "HOST1" and "PORT1" may be the empty
           string, meaning "any host/port". "HOST2" and "PORT2" may also be
           the empty string, meaning "use the request's original host/port".

           A "host" specified to this option is compared as a string, so it
           needs to match the name used in request URL. It can be either
           numerical such as "127.0.0.1" or the full host name such as
           "example.org".

           This option can be used many times to add many connect rules.

           See also --resolve and -H, --header. Added in 7.49.0.

      -C, --continue-at <offset>
           Continue/Resume a previous file transfer at the given offset. The
           given offset is the exact number of bytes that will be skipped,
           counting from the beginning of the source file before it is
           transferred to the destination.  If used with uploads, the FTP
           server command SIZE will not be used by curl.

           Use "-C -" to tell curl to automatically find out where/how to
           resume the transfer. It then uses the given output/input files to
           figure that out.

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

           See also -r, --range.

      -c, --cookie-jar <filename>
           (HTTP) Specify to which file you want curl to write all cookies
           after a completed operation. Curl writes all cookies from its



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           in-memory cookie storage to the given file at the end of
           operations. If no cookies are known, no data will be written. The
           file will be written using the Netscape cookie file format. If
           you set the file name to a single dash, "-", the cookies will be
           written to stdout.

           This command line option will activate the cookie engine that
           makes curl record and use cookies. Another way to activate it is
           to use the -b, --cookie option.

           If the cookie jar can't be created or written to, the whole curl
           operation won't fail or even report an error clearly. Using -v,
           --verbose will get a warning displayed, but that is the only
           visible feedback you get about this possibly lethal situation.

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

      -b, --cookie <data|filename>
           (HTTP) Pass the data to the HTTP server in the Cookie header. It
           is supposedly the data previously received from the server in a
           "Set-Cookie:" line.  The data should be in the format
           "NAME1=VALUE1; NAME2=VALUE2".

           If no '=' symbol is used in the argument, it is instead treated
           as a filename to read previously stored cookie from. This option
           also activates the cookie engine which will make curl record
           incoming cookies, which may be handy if you're using this in
           combination with the -L, --location option or do multiple URL
           transfers on the same invoke. If the file name is exactly a minus
           ("-"), curl will instead read the contents from stdin.

           The file format of the file to read cookies from should be plain
           HTTP headers (Set-Cookie style) or the Netscape/Mozilla cookie
           file format.

           The file specified with -b, --cookie is only used as input. No
           cookies will be written to the file. To store cookies, use the
           -c, --cookie-jar option.

           Exercise caution if you are using this option and multiple
           transfers may occur.  If you use the NAME1=VALUE1; format, or in
           a file use the Set-Cookie format and don't specify a domain, then
           the cookie is sent for any domain (even after redirects are
           followed) and cannot be modified by a server-set cookie. If the
           cookie engine is enabled and a server sets a cookie of the same
           name then both will be sent on a future transfer to that server,
           likely not what you intended.  To address these issues set a
           domain in Set-Cookie (doing that will include sub domains) or use



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           the Netscape format.

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

           Users very often want to both read cookies from a file and write
           updated cookies back to a file, so using both -b, --cookie and
           -c, --cookie-jar in the same command line is common.

      --create-dirs
           When used in conjunction with the -o, --output option, curl will
           create the necessary local directory hierarchy as needed. This
           option creates the dirs mentioned with the -o, --output option,
           nothing else. If the --output file name uses no dir or if the
           dirs it mentions already exist, no dir will be created.

           Created dirs are made with mode 0750 on unix style file systems.

           To create remote directories when using FTP or SFTP, try --ftp-
           create-dirs.

      --crlf
           (FTP SMTP) Convert LF to CRLF in upload. Useful for MVS (OS/390).

           (SMTP added in 7.40.0)

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

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

           Added in 7.19.7.

      --data-ascii <data>
           (HTTP) This is just an alias for -d, --data.

      --data-binary <data>
           (HTTP) This posts data exactly as specified with no extra
           processing whatsoever.

           If you start the data with the letter @, the rest should be a
           filename.  Data is posted in a similar manner as -d, --data does,
           except that newlines and carriage returns are preserved and
           conversions are never done.

           Like -d, --data the default content-type sent to the server is
           application/x-www-form-urlencoded. If you want the data to be
           treated as arbitrary binary data by the server then set the



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           content-type to octet-stream: -H "Content-Type:
           application/octet-stream".

           If this option is used several times, the ones following the
           first will append data as described in -d, --data.

      --data-raw <data>
           (HTTP) This posts data similarly to -d, --data but without the
           special interpretation of the @ character.

           See also -d, --data. Added in 7.43.0.

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

           To be CGI-compliant, the <data> part should begin with a name
           followed by a separator and a content specification. The <data>
           part can be passed to curl using one of the following syntaxes:

           content
                This will make curl URL-encode the content and pass that on.
                Just be careful so that the content doesn't contain any = or
                @ symbols, as that will then make the syntax match one of
                the other cases below!

           =content
                This will make curl URL-encode the content and pass that on.
                The preceding = symbol is not included in the data.

           name=content
                This will make curl URL-encode the content part and pass
                that on. Note that the name part is expected to be URL-
                encoded already.

           @filename
                This will make curl load data from the given file (including
                any newlines), URL-encode that data and pass it on in the
                POST.

           name@filename
                This will make curl load data from the given file (including
                any newlines), URL-encode that data and pass it on in the
                POST. The name part gets an equal sign appended, resulting
                in name=urlencoded-file-content. Note that the name is
                expected to be URL-encoded already.

      See also -d, --data and --data-raw. Added in 7.18.0.




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      -d, --data <data>
           (HTTP MQTT) Sends the specified data in a POST request to the
           HTTP server, in the same way that a browser does when a user has
           filled in an HTML form and presses the submit button. This will
           cause curl to pass the data to the server using the content-type
           application/x-www-form-urlencoded.  Compare to -F, --form.

           --data-raw is almost the same but does not have a special
           interpretation of the @ character. To post data purely binary,
           you should instead use the --data-binary option.  To URL-encode
           the value of a form field you may use --data-urlencode.

           If any of these options is used more than once on the same
           command line, the data pieces specified will be merged together
           with a separating &-symbol. Thus, using '-d name=daniel -d
           skill=lousy' would generate a post chunk that looks like
           'name=daniel&skill=lousy'.

           If you start the data with the letter @, the rest should be a
           file name to read the data from, or - if you want curl to read
           the data from stdin. Posting data from a file named 'foobar'
           would thus be done with -d, --data @foobar. When -d, --data is
           told to read from a file like that, carriage returns and newlines
           will be stripped out. If you don't want the @ character to have a
           special interpretation use --data-raw instead.

           See also --data-binary and --data-urlencode and --data-raw. This
           option overrides -F, --form and -I, --head and -T, --upload-file.

      --delegation <LEVEL>
           (GSS/kerberos) Set LEVEL to tell the server what it is allowed to
           delegate when it comes to user credentials.

           none Don't allow any delegation.

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

           always
                Unconditionally allow the server to delegate.

      --digest
           (HTTP) Enables HTTP Digest authentication. This is an
           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.




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

           See also -u, --user and --proxy-digest and --anyauth. This option
           overrides --basic and --ntlm and --negotiate.

      --disable-eprt
           (FTP) Tell curl to disable the use of the EPRT and LPRT commands
           when doing active FTP transfers. Curl will normally always first
           attempt to use EPRT, then LPRT before using PORT, but with this
           option, it will use PORT right away. EPRT and LPRT are extensions
           to the original FTP protocol, and may not work on all servers,
           but they enable more functionality in a better way than the
           traditional PORT command.

           --eprt can be used to explicitly enable EPRT again and --no-eprt
           is an alias for --disable-eprt.

           If the server is accessed using IPv6, this option will have no
           effect as EPRT is necessary then.

           Disabling EPRT only changes the active behavior. If you want to
           switch to passive mode you need to not use -P, --ftp-port or
           force it with --ftp-pasv.

      --disable-epsv
           (FTP) (FTP) Tell curl to disable the use of the EPSV command when
           doing passive FTP transfers. Curl will normally always first
           attempt to use EPSV before PASV, but with this option, it will
           not try using EPSV.

           --epsv can be used to explicitly enable EPSV again and --no-epsv
           is an alias for --disable-epsv.

           If the server is an IPv6 host, this option will have no effect as
           EPSV is necessary then.

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

      -q, --disable
           If used as the first parameter on the command line, the curlrc
           config file will not be read and used. See the -K, --config for
           details on the default config file search path.

      --disallow-username-in-url
           (HTTP) This tells curl to exit if passed a url containing a
           username.

           See also --proto. Added in 7.61.0.



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      --dns-interface <interface>
           (DNS) Tell curl to send outgoing DNS requests through
           <interface>. This option is a counterpart to --interface (which
           does not affect DNS). The supplied string must be an interface
           name (not an address).

           See also --dns-ipv4-addr and --dns-ipv6-addr. --dns-interface
           requires that the underlying libcurl was built to support c-ares.
           Added in 7.33.0.

      --dns-ipv4-addr <address>
           (DNS) Tell curl to bind to <ip-address> when making IPv4 DNS
           requests, so that the DNS requests originate from this address.
           The argument should be a single IPv4 address.

           See also --dns-interface and --dns-ipv6-addr. --dns-ipv4-addr
           requires that the underlying libcurl was built to support c-ares.
           Added in 7.33.0.

      --dns-ipv6-addr <address>
           (DNS) Tell curl to bind to <ip-address> when making IPv6 DNS
           requests, so that the DNS requests originate from this address.
           The argument should be a single IPv6 address.

           See also --dns-interface and --dns-ipv4-addr. --dns-ipv6-addr
           requires that the underlying libcurl was built to support c-ares.
           Added in 7.33.0.

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

           --dns-servers requires that the underlying libcurl was built to
           support c-ares. Added in 7.33.0.

      --doh-url <URL>
           (all) Specifies which DNS-over-HTTPS (DOH) server to use to
           resolve hostnames, instead of using the default name resolver
           mechanism. The URL must be HTTPS.

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

           Added in 7.62.0.

      -D, --dump-header <filename>
           (HTTP FTP) Write the received protocol headers to the specified
           file.



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           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.

           If no headers are received, the use of this option will create an
           empty file.

           When used in FTP, the FTP server response lines are considered
           being "headers" and thus are saved there.

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

           See also -o, --output.

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

           See also --random-file.

      --engine <name>
           (TLS) Select the OpenSSL crypto engine to use for cipher
           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.

      --etag-compare <file>
           (HTTP) This option makes a conditional HTTP request for the
           specific ETag read from the given file by sending a custom If-
           None-Match header using the extracted ETag.

           For correct results, make sure that specified file contains only
           a single line with a desired ETag. An empty file is parsed as an
           empty ETag.

           Use the option --etag-save to first save the ETag from a
           response, and then use this option to compare using the saved
           ETag in a subsequent request.

           OMPARISON: There are 2 types of comparison or ETags, Weak and
           Strong.  This option expects, and uses a strong comparison.

           Added in 7.68.0.

      --etag-save <file>
           (HTTP) This option saves an HTTP ETag to the specified file. Etag



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           is usually part of headers returned by a request. When server
           sends an ETag, it must be enveloped by a double quote. This
           option extracts the ETag without the double quotes and saves it
           into the <file>.

           A server can send a week ETag which is prefixed by "W/". This
           identifier is not considered, and only relevant ETag between
           quotation marks is parsed.

           It an ETag wasn't send by the server or it cannot be parsed, and
           empty file is created.

           Added in 7.68.0.

      --expect100-timeout <seconds>
           (HTTP) Maximum time in seconds that you allow curl to wait for a
           100-continue response when curl emits an Expects: 100-continue
           header in its request. By default curl will wait one second. This
           option accepts decimal values! When curl stops waiting, it will
           continue as if the response has been received.

           See also --connect-timeout. Added in 7.47.0.

      --fail-early
           Fail and exit on the first detected transfer error.

           When curl is used to do multiple transfers on the command line,
           it will attempt to operate on each given URL, one by one. By
           default, it will ignore errors if there are more URLs given and
           the last URL's success will determine the error code curl
           returns. So early failures will be "hidden" by subsequent
           successful transfers.

           Using this option, curl will instead return an error on the first
           transfer that fails, independent of the amount of URLs that are
           given on the command line. This way, no transfer failures go
           undetected by scripts and similar.

           This option is global and does not need to be specified for each
           use of -:, --next.

           This option does not imply -f, --fail, which causes transfers to
           fail due to the server's HTTP status code. You can combine the
           two options, however note -f, --fail is not global and is
           therefore contained by -:, --next.

           Added in 7.52.0.

      -f, --fail



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           (HTTP) Fail silently (no output at all) on server errors. This is
           mostly done to better enable scripts etc to better deal with
           failed attempts. In normal cases when an HTTP server fails to
           deliver a document, it returns an HTML document stating so (which
           often also describes why and more). This flag will prevent curl
           from outputting that and return error 22.

           This method is not fail-safe and there are occasions where non-
           successful response codes will slip through, especially when
           authentication is involved (response codes 401 and 407).

      --false-start
           (TLS) Tells curl to use false start during the TLS handshake.
           False start is a mode where a TLS client will start sending
           application data before verifying the server's Finished message,
           thus saving a round trip when performing a full handshake.

           This is currently only implemented in the NSS and Secure
           Transport (on iOS 7.0 or later, or OS X 10.9 or later) backends.

           Added in 7.42.0.

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

           See also -F, --form.

      -F, --form <name=content>
           (HTTP SMTP IMAP) For HTTP protocol family, 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.

           For SMTP and IMAP protocols, this is the mean to compose a
           multipart mail message to transmit.

           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.




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           Tell curl to read content from stdin instead of a file by using -
           as filename. This goes for both @ and < constructs. When stdin is
           used, the contents is buffered in memory first by curl to
           determine its size and allow a possible resend.  Defining a
           part's data from a named non-regular file (such as a named pipe
           or similar) is unfortunately not subject to buffering and will be
           effectively read at transmission time; since the full size is
           unknown before the transfer starts, such data is sent as chunks
           by HTTP and rejected by IMAP.

           Example: send an image to an HTTP server, where 'profile' is the
           name of the form-field to which the file portrait.jpg will be the
           input:

            curl -F profile=@portrait.jpg https://example.com/upload.cgi

           Example: send your name and shoe size in two text fields to the
           server:

            curl -F name=John -F shoesize=11 https://example.com/

           Example: send your essay in a text field to the server. Send it
           as a plain text field, but get the contents for it from a local
           file:

            curl -F "story=<hugefile.txt" https://example.com/

           You can also tell curl what Content-Type to use by using 'type=',
           in a manner similar to:

            curl -F "web=@index.html;type=text/html" example.com

           or

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

           You can also explicitly change the name field of a file upload
           part by setting filename=, like this:

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

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

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

           or




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

           Note that if a filename/path is quoted by double-quotes, any
           double-quote or backslash within the filename must be escaped by
           backslash.

           Quoting must also be applied to non-file data if it contains
           semicolons, leading/trailing spaces or leading double quotes:

            curl -F 'colors="red; green; blue";type=text/x-myapp'
           example.com

           You can add custom headers to the field by setting headers=, like

             curl -F "submit=OK;headers=\"X-submit-type: OK\"" example.com

           or

             curl -F "submit=OK;headers=@headerfile" example.com

           The headers= keyword may appear more that once and above notes
           about quoting apply. When headers are read from a file, Empty
           lines and lines starting with '#' are comments and ignored; each
           header can be folded by splitting between two words and starting
           the continuation line with a space; embedded carriage-returns and
           trailing spaces are stripped.  Here is an example of a header
           file contents:

             # This file contain two headers.
             X-header-1: this is a header

             # The following header is folded.
             X-header-2: this is
              another header


           To support sending multipart mail messages, the syntax is
           extended as follows:
           - name can be omitted: the equal sign is the first character of
           the argument,
           - if data starts with '(', this signals to start a new multipart:
           it can be followed by a content type specification.
           - a multipart can be terminated with a '=)' argument.

           Example: the following command sends an SMTP mime e-mail
           consisting in an inline part in two alternative formats: plain
           text and HTML. It attaches a text file:

            curl -F '=(;type=multipart/alternative' \



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                    -F '=plain text message' \
                    -F '= <body>HTML message</body>;type=text/html' \
                 -F '=)' -F '=@textfile.txt' ...  smtp://example.com

           Data can be encoded for transfer using encoder=. Available
           encodings are binary and 8bit that do nothing else than adding
           the corresponding Content-Transfer-Encoding header, 7bit that
           only rejects 8-bit characters with a transfer error, quoted-
           printable and base64 that encodes data according to the
           corresponding schemes, limiting lines length to 76 characters.

           Example: send multipart mail with a quoted-printable text message
           and a base64 attached file:

            curl -F '=text message;encoder=quoted-printable' \
                 -F '=@localfile;encoder=base64' ... smtp://example.com

           See further examples and details in the MANUAL.

           This option can be used multiple times.

           This option overrides -d, --data and -I, --head and -T, --
           upload-file.

      --ftp-account <data>
           (FTP) When an FTP server asks for "account data" after user name
           and password has been provided, this data is sent off using the
           ACCT command.

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

           Added in 7.13.0.

      --ftp-alternative-to-user <command>
           (FTP) If authenticating with the USER and PASS commands fails,
           send this command.  When connecting to Tumbleweed's Secure
           Transport server over FTPS using a client certificate, using
           "SITE AUTH" will tell the server to retrieve the username from
           the certificate.

           Added in 7.15.5.

      --ftp-create-dirs
           (FTP SFTP) When an FTP or SFTP URL/operation uses a path that
           doesn't currently exist on the server, the standard behavior of
           curl is to fail. Using this option, curl will instead attempt to
           create missing directories.

           See also --create-dirs.



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      --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.

           If this option is used several times, only the first one is used.
           Undoing an enforced passive really isn't doable but you must then
           instead enforce the correct -P, --ftp-port again.

           Passive mode means that curl will try the EPSV command first and
           then PASV, unless --disable-epsv is used.

           See also --disable-epsv. Added in 7.11.0.

      -P, --ftp-port <address>
           (FTP) Reverses the default initiator/listener roles when
           connecting with FTP. This option makes curl use active mode. curl
           then tells the server to connect back to the client's specified
           address and port, while passive mode asks the server to setup an
           IP address and port for it to connect to. <address> should be one
           of:

           interface
                e.g. "eth0" to specify which interface's IP address you want
                to use (Unix only)



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           IP address
                e.g. "192.168.10.1" to specify the exact IP address

           host name
                e.g. "my.host.domain" to specify the machine

           -    make curl pick the same IP address that is already used for
                the control connection

      If this option is used several times, the last one will be used.
      Disable the use of PORT with --ftp-pasv. Disable the attempt to use
      the EPRT command instead of PORT by using --disable-eprt. EPRT is
      really PORT++.

      Since 7.19.5, you can append ":[start]-[end]" to the right of the
      address, to tell curl what TCP port range to use. That means you
      specify a port range, from a lower to a higher number. A single number
      works as well, but do note that it increases the risk of failure since
      the port may not be available.

      See also --ftp-pasv and --disable-eprt.

      --ftp-pret
           (FTP) Tell curl to send a PRET command before PASV (and EPSV).
           Certain FTP servers, mainly drftpd, require this non-standard
           command for directory listings as well as up and downloads in
           PASV mode.

           Added in 7.20.0.

      --ftp-skip-pasv-ip
           (FTP) Tell curl to not use the IP address the server suggests in
           its response to curl's PASV command when curl connects the data
           connection. Instead curl will re-use the same IP address it
           already uses for the control connection.

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

           See also --ftp-pasv. Added in 7.14.2.

      --ftp-ssl-ccc-mode <active/passive>
           (FTP) Sets the CCC mode. The passive mode will not initiate the
           shutdown, but instead wait for the server to do it, and will not
           reply to the shutdown from the server. The active mode initiates
           the shutdown and waits for a reply from the server.

           See also --ftp-ssl-ccc. Added in 7.16.2.




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      --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 also --ssl and --ftp-ssl-ccc-mode. Added in 7.16.1.

      --ftp-ssl-control
           (FTP) Require SSL/TLS for the FTP login, clear for transfer.
           Allows secure authentication, but non-encrypted data transfers
           for efficiency.  Fails the transfer if the server doesn't support
           SSL/TLS.

           Added in 7.16.0.

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

           If used in combination with -I, --head, the POST data will
           instead be appended to the URL with a HEAD request.

           If this option is used several times, only the first one is used.
           This is because undoing a GET doesn't make sense, but you should
           then instead enforce the alternative method you prefer.

      -g, --globoff
           This option switches off the "URL globbing parser". When you set
           this option, you can specify URLs that contain the letters {}[]
           without having them being interpreted by curl itself. Note that
           these letters are not normal legal URL contents but they should
           be encoded according to the URI standard.

      --happy-eyeballs-timeout-ms <milliseconds>
           Happy eyeballs is an algorithm that attempts to connect to both
           IPv4 and IPv6 addresses for dual-stack hosts, preferring IPv6
           first for the number of milliseconds. If the IPv6 address cannot
           be connected to within that time then a connection attempt is
           made to the IPv4 address in parallel. The first connection to be
           established is the one that is used.

           The range of suggested useful values is limited. Happy Eyeballs
           RFC 6555 says "It is RECOMMENDED that connection attempts be
           paced 150-250 ms apart to balance human factors against network
           load." libcurl currently defaults to 200 ms. Firefox and Chrome
           currently default to 300 ms.



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

           Added in 7.59.0.

      --haproxy-protocol
           (HTTP) Send a HAProxy PROXY protocol v1 header at the beginning
           of the connection. This is used by some load balancers and
           reverse proxies to indicate the client's true IP address and
           port.

           This option is primarily useful when sending test requests to a
           service that expects this header.

           Added in 7.60.0.

      -I, --head
           (HTTP FTP FILE) Fetch the headers only! HTTP-servers feature the
           command HEAD which this uses to get nothing but the header of a
           document. When used on an FTP or FILE file, curl displays the
           file size and last modification time only.

      -H, --header <header/@file>
           (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.

           Starting in 7.55.0, this option can take an argument in @filename
           style, which then adds a header for each line in the input file.
           Using @- will make curl read the header file from stdin.

           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.




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           Example:

            curl -H "X-First-Name: Joe" http://example.com/

           WARNING: headers set with this option will be set in all requests
           - even after redirects are followed, like when told with -L, --
           location. This can lead to the header being sent to other hosts
           than the original host, so sensitive headers should be used with
           caution combined with following redirects.

           This option can be used multiple times to add/replace/remove
           multiple headers.

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

      --hostpubmd5 <md5>
           (SFTP SCP) Pass a string containing 32 hexadecimal digits. The
           string should be the 128 bit MD5 checksum of the remote host's
           public key, curl will refuse the connection with the host unless
           the md5sums match.

           Added in 7.17.1.

      --http0.9
           (HTTP) Tells curl to be fine with HTTP version 0.9 response.

           HTTP/0.9 is a completely headerless response and therefore you
           can also connect with this to non-HTTP servers and still get a
           response since curl will simply transparently downgrade - if
           allowed.

           Since curl 7.66.0, HTTP/0.9 is disabled by default.

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

           This option overrides --http1.1 and --http2.

      --http1.1
           (HTTP) Tells curl to use HTTP version 1.1.

           This option overrides -0, --http1.0 and --http2. Added in 7.33.0.

      --http2-prior-knowledge
           (HTTP) Tells curl to issue its non-TLS HTTP requests using HTTP/2
           without HTTP/1.1 Upgrade. It requires prior knowledge that the



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           server supports HTTP/2 straight away. HTTPS requests will still
           do HTTP/2 the standard way with negotiated protocol version in
           the TLS handshake.

           --http2-prior-knowledge requires that the underlying libcurl was
           built to support HTTP/2. This option overrides --http1.1 and -0,
           --http1.0 and --http2. Added in 7.49.0.

      --http2
           (HTTP) Tells curl to use HTTP version 2.

           See also --http1.1 and --http3. --http2 requires that the
           underlying libcurl was built to support HTTP/2. This option
           overrides --http1.1 and -0, --http1.0 and --http2-prior-
           knowledge. Added in 7.33.0.

      --http3
           (HTTP) WARNING: this option is experimental. Do not use in
           production.

           Tells curl to use HTTP version 3 directly to the host and port
           number used in the URL. A normal HTTP/3 transaction will be done
           to a host and then get redirected via Alt-SVc, but this option
           allows a user to circumvent that when you know that the target
           speaks HTTP/3 on the given host and port.

           This option will make curl fail if a QUIC connection cannot be
           established, it cannot fall back to a lower HTTP version on its
           own.

           See also --http1.1 and --http2. --http3 requires that the
           underlying libcurl was built to support HTTP/3. This option
           overrides --http1.1 and -0, --http1.0 and --http2 and --http2-
           prior-knowledge. Added in 7.66.0.

      --ignore-content-length
           (FTP HTTP) For HTTP, Ignore the Content-Length header. This is
           particularly useful for servers running Apache 1.x, which will
           report incorrect Content-Length for files larger than 2
           gigabytes.

           For FTP (since 7.46.0), skip the RETR command to figure out the
           size before downloading a file.

      -i, --include
           Include the HTTP response headers in the output. The HTTP
           response headers can include things like server name, cookies,
           date of the document, HTTP version and more...




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           To view the request headers, consider the -v, --verbose option.

           See also -v, --verbose.

      -k, --insecure
           (TLS) By default, every SSL connection curl makes is verified to
           be secure. This option allows curl to proceed and operate even
           for server connections otherwise considered insecure.

           The server connection is verified by making sure the server's
           certificate contains the right name and verifies successfully
           using the cert store.

           See this online resource for further details:
            https://curl.haxx.se/docs/sslcerts.html

           See also --proxy-insecure and --cacert.

      --interface <name>

           Perform an operation using a specified interface. You can enter
           interface name, IP address or host name. An example could look
           like:

            curl --interface eth0:1 https://www.example.com/

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

           On Linux it can be used to specify a VRF, but the binary needs to
           either have CAP_NET_RAW or to be run as root. More information
           about Linux VRF:
           https://www.kernel.org/doc/Documentation/networking/vrf.txt

           See also --dns-interface.

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

           See also --http1.1 and --http2. This option overrides -6, --ipv6.

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

           See also --http1.1 and --http2. This option overrides -4, --ipv4.

      -j, --junk-session-cookies
           (HTTP) When curl is told to read cookies from a given file, this



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           option will make it discard all "session cookies". This will
           basically have the same effect as if a new session is started.
           Typical browsers always discard session cookies when they're
           closed down.

           See also -b, --cookie and -c, --cookie-jar.

      --keepalive-time <seconds>
           This option sets the time a connection needs to remain idle
           before sending keepalive probes and the time between individual
           keepalive probes. It is currently effective on operating systems
           offering the TCP_KEEPIDLE and TCP_KEEPINTVL socket options
           (meaning Linux, recent AIX, HP-UX and more). This option has no
           effect if --no-keepalive is used.

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

           Added in 7.18.0.

      --key-type <type>
           (TLS) Private key file type. Specify which type your --key
           provided private key is. DER, PEM, and ENG are supported. If not
           specified, PEM is assumed.

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

      --key <key>
           (TLS SSH) Private key file name. Allows you to provide your
           private key in this separate file. For SSH, if not specified,
           curl tries the following candidates in order: '~/.ssh/id_rsa',
           '~/.ssh/id_dsa', './id_rsa', './id_dsa'.

           If curl is built against OpenSSL library, and the engine pkcs11
           is available, then a PKCS#11 URI (RFC 7512) can be used to
           specify a private key located in a PKCS#11 device. A string
           beginning with "pkcs11:" will be interpreted as a PKCS#11 URI. If
           a PKCS#11 URI is provided, then the --engine option will be set
           as "pkcs11" if none was provided and the --key-type option will
           be set as "ENG" if none was provided.

           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.




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

           --krb requires that the underlying libcurl was built to support
           Kerberos.

      --libcurl <file>
           Append this option to any ordinary curl command line, and you
           will get a libcurl-using C source code written to the file that
           does the equivalent of what your command-line operation does!

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

           Added in 7.16.1.

      --limit-rate <speed>
           Specify the maximum transfer rate you want curl to use - for both
           downloads and uploads. This feature is useful if you have a
           limited pipe and you'd like your transfer not to use your entire
           bandwidth. To make it slower than it otherwise would be.

           The given speed is measured in bytes/second, unless a suffix is
           appended.  Appending 'k' or 'K' will count the number as
           kilobytes, 'm' or 'M' makes it megabytes, while 'g' or 'G' makes
           it gigabytes. Examples: 200K, 3m and 1G.

           If you also use the -Y, --speed-limit option, that option will
           take precedence and might cripple the rate-limiting slightly, to
           help keeping the speed-limit logic working.

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

      -l, --list-only
           (FTP POP3) (FTP) When listing an FTP directory, this switch
           forces a name-only view. This is especially useful if the user
           wants to machine-parse the contents of an FTP directory since the
           normal directory view doesn't use a standard look or format. When
           used like this, the option causes a NLST command to be sent to
           the server instead of LIST.

           Note: Some FTP servers list only files in their response to NLST;
           they do not include sub-directories and symbolic links.

           (POP3) When retrieving a specific email from POP3, this switch
           forces a LIST command to be performed instead of RETR. This is
           particularly useful if the user wants to see if a specific
           message id exists on the server and what size it is.

           Note: When combined with -X, --request, this option can be used



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           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 4.0.

      --local-port <num/range>
           Set a preferred single number or range (FROM-TO) of local port
           numbers to use for the connection(s).  Note that port numbers by
           nature are a scarce resource that will be busy at times so
           setting this range to something too narrow might cause
           unnecessary connection setup failures.

           Added in 7.15.2.

      --location-trusted
           (HTTP) Like -L, --location, but will allow sending the name +
           password to all hosts that the site may redirect to. This may or
           may not introduce a security breach if the site redirects you to
           a site to which you'll send your authentication info (which is
           plaintext in the case of HTTP Basic authentication).

           See also -u, --user.

      -L, --location
           (HTTP) If the server reports that the requested page has moved to
           a different location (indicated with a Location: header and a 3XX
           response code), this option will make curl redo the request on
           the new place. If used together with -i, --include or -I, --head,
           headers from all requested pages will be shown. When
           authentication is used, curl only sends its credentials to the
           initial host. If a redirect takes curl to a different host, it
           won't be able to intercept the user+password. See also --
           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 if the request is a POST, 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 POST requests to GET after a 30x
           response by using the dedicated options for that: --post301, --
           post302 and --post303.

           The method set with -X, --request overrides the method curl would
           otherwise select to use.




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      --login-options <options>
           (IMAP POP3 SMTP) Specify the login options to use during server
           authentication.

           You can use the login options to specify protocol specific
           options that may be used during authentication. At present only
           IMAP, POP3 and SMTP support login options. For more information
           about the login options please see RFC 2384, RFC 5092 and IETF
           draft draft-earhart-url-smtp-00.txt

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

           Added in 7.34.0.

      --mail-auth <address>
           (SMTP) Specify a single address. This will be used to specify the
           authentication address (identity) of a submitted message that is
           being relayed to another server.

           See also --mail-rcpt and --mail-from. Added in 7.25.0.

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

           See also --mail-rcpt and --mail-auth. Added in 7.20.0.

      --mail-rcpt-allowfails
           (SMTP) When sending data to multiple recipients, by default curl
           will abort SMTP conversation if at least one of the recipients
           causes RCPT TO command to return an error.

           The default behavior can be changed by passing --mail-rcpt-
           allowfails command-line option which will make curl ignore errors
           and proceed with the remaining valid recipients.

           In case when all recipients cause RCPT TO command to fail, curl
           will abort SMTP conversation and return the error received from
           to the last RCPT TO command.  Added in 7.69.0.

      --mail-rcpt <address>
           (SMTP) Specify a single address, user name or mailing list name.
           Repeat this option several times to send to multiple recipients.

           When performing a mail transfer, the recipient should specify a
           valid email address to send the mail to.

           When performing an address verification (VRFY command), the
           recipient should be specified as the user name or user name and



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           domain (as per Section 3.5 of RFC5321). (Added in 7.34.0)

           When performing a mailing list expand (EXPN command), the
           recipient should be specified using the mailing list name, such
           as "Friends" or "London-Office".  (Added in 7.34.0)

           Added in 7.20.0.

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

      --max-filesize <bytes>
           Specify the maximum size (in bytes) of a file to download. If the
           file requested is larger than this value, the transfer will not
           start and curl will return with exit code 63.

           A size modifier may be used. For example, 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. (Added in 7.58.0)

           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.

           See also --limit-rate.

      --max-redirs <num>
           (HTTP) Set maximum number of redirection-followings allowed. When
           -L, --location is used, is used to prevent curl from following
           redirections too much. By default, the limit is set to 50
           redirections. Set this option to -1 to make it unlimited.

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

      -m, --max-time <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.

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

           See also --connect-timeout.

      --metalink



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           This option can tell curl to parse and process a given URI as
           Metalink file (both version 3 and 4 (RFC 5854) are supported) and
           make use of the mirrors listed within for failover if there are
           errors (such as the file or server not being available). It will
           also verify the hash of the file after the download completes.
           The Metalink file itself is downloaded and processed in memory
           and not stored in the local file system.

           Example to use a remote Metalink file:

            curl --metalink http://www.example.com/example.metalink

           To use a Metalink file in the local file system, use FILE
           protocol (file://):

            curl --metalink file://example.metalink

           Please note that if FILE protocol is disabled, there is no way to
           use a local Metalink file at the time of this writing. Also note
           that if --metalink and -i, --include are used together, --include
           will be ignored. This is because including headers in the
           response will break Metalink parser and if the headers are
           included in the file described in Metalink file, hash check will
           fail.

           --metalink requires that the underlying libcurl was built to
           support metalink. Added in 7.27.0.

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

           This option requires a library built with GSS-API or SSPI
           support. Use -V, --version to see if your curl supports GSS-
           API/SSPI or SPNEGO.

           When using this option, you must also provide a fake -u, --user
           option to activate the authentication code properly. Sending a
           '-u :' is enough as the user name and password from the -u, --
           user option aren't actually used.

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

           See also --basic and --ntlm and --anyauth and --proxy-negotiate.

      --netrc-file <filename>
           This option is similar to -n, --netrc, except that you provide
           the path (absolute or relative) to the netrc file that curl
           should use.  You can only specify one netrc file per invocation.
           If several --netrc-file options are provided, the last one will



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           be used.

           It will abide by --netrc-optional if specified.

           This option overrides -n, --netrc. Added in 7.21.5.

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

           See also --netrc-file. This option overrides -n, --netrc.

      -n, --netrc
           Makes curl scan the .netrc (_netrc on Windows) file in the user's
           home directory for login name and password. This is typically
           used for FTP on Unix. If used with HTTP, curl will enable user
           authentication. See netrc(5) ftp(1) for details on the file
           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

      -:, --next
           Tells curl to use a separate operation for the following URL and
           associated options. This allows you to send several URL requests,
           each with their own specific options, for example, such as
           different user names or custom requests for each.

           -:, --next will reset all local options and only global ones will
           have their values survive over to the operation following the -:,
           --next instruction. Global options include -v, --verbose, --
           trace, --trace-ascii and --fail-early.

           For example, you can do both a GET and a POST in a single command
           line:

            curl www1.example.com --next -d postthis www2.example.com

           Added in 7.36.0.

      --no-alpn
           (HTTPS) Disable the ALPN TLS extension. ALPN is enabled by
           default if libcurl was built with an SSL library that supports



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           ALPN. ALPN is used by a libcurl that supports HTTP/2 to negotiate
           HTTP/2 support with the server during https sessions.

           See also --no-npn and --http2. --no-alpn requires that the
           underlying libcurl was built to support TLS. Added in 7.36.0.

      -N, --no-buffer
           Disables the buffering of the output stream. In normal work
           situations, curl will use a standard buffered output stream that
           will have the effect that it will output the data in chunks, not
           necessarily exactly when the data arrives.  Using this option
           will disable that buffering.

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

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

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

      --no-npn
           (HTTPS) Disable the NPN TLS extension. NPN is enabled by default
           if libcurl was built with an SSL library that supports NPN. NPN
           is used by a libcurl that supports HTTP/2 to negotiate HTTP/2
           support with the server during https sessions.

           See also --no-alpn and --http2. --no-npn requires that the
           underlying libcurl was built to support TLS. Added in 7.36.0.

      --no-progress-meter
           Option to switch off the progress meter output without muting or
           otherwise affecting warning and informational messages like -s,
           --silent does.

           Note that this is the negated option name documented. You can
           thus use --progress-meter to enable the progress meter again.

           See also -v, --verbose and -s, --silent. Added in 7.67.0.

      --no-sessionid
           (TLS) Disable curl's use of SSL session-ID caching.  By default
           all transfers are done using the cache. Note that while nothing
           should ever get hurt by attempting to reuse SSL session-IDs,
           there seem to be broken SSL implementations in the wild that may
           require you to disable this in order for you to succeed.




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

           Added in 7.16.0.

      --noproxy <no-proxy-list>
           Comma-separated list of hosts which do not use a proxy, if one is
           specified.  The only wildcard is a single * character, which
           matches all hosts, and effectively disables the proxy. Each name
           in this list is matched as either a domain which contains the
           hostname, or the hostname itself. For example, local.com would
           match local.com, local.com:80, and www.local.com, but not
           www.notlocal.com.

           Since 7.53.0, This option overrides the environment variables
           that disable the proxy. If there's an environment variable
           disabling a proxy, you can set noproxy list to "" to override it.

           Added in 7.19.4.

      --ntlm-wb
           (HTTP) Enables NTLM much in the style --ntlm does, but hand over
           the authentication to the separate binary ntlmauth application
           that is executed when needed.

           See also --ntlm and --proxy-ntlm.

      --ntlm
           (HTTP) Enables NTLM authentication. The NTLM authentication
           method was designed by Microsoft and is used by IIS web servers.
           It is a proprietary protocol, reverse-engineered by clever 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.

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

           See also --proxy-ntlm. --ntlm requires that the underlying
           libcurl was built to support TLS. This option overrides --basic
           and --negotiate and --digest and --anyauth.

      --oauth2-bearer <token>
           (IMAP POP3 SMTP HTTP) 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



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           -u, --user options.

           The Bearer Token and user name are formatted according to RFC
           6750.

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

      -o, --output <file>
           Write output to <file> instead of stdout. If you are using {} or
           [] to fetch multiple documents, you should quote the URL and you
           can use '#' followed by a number in the <file> specifier. That
           variable will be replaced with the current string for the URL
           being fetched. Like in:

            curl "http://{one,two}.example.com" -o "file_#1.txt"

           or use several variables like:

            curl "http://{site,host}.host[1-5].com" -o "#1_#2"

           You may use this option as many times as the number of URLs you
           have. For example, if you specify two URLs on the same command
           line, you can use it like this:

             curl -o aa example.com -o bb example.net

           and the order of the -o options and the URLs doesn't matter, just
           that the first -o is for the first URL and so on, so the above
           command line can also be written as

             curl example.com example.net -o aa -o bb

           See also the --create-dirs option to create the local directories
           dynamically. Specifying the output as '-' (a single dash) will
           force the output to be done to stdout.

           See also -O, --remote-name and --remote-name-all and -J, --
           remote-header-name.

      --parallel-immediate
           When doing parallel transfers, this option will instruct curl
           that it should rather prefer opening up more connections in
           parallel at once rather than waiting to see if new transfers can
           be added as multiplexed streams on another connection.

           See also -Z, --parallel and --parallel-max. Added in 7.68.0.

      --parallel-max
           When asked to do parallel transfers, using -Z, --parallel, this



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           option controls the maximum amount of transfers to do
           simultaneously.

           The default is 50.

           See also -Z, --parallel. Added in 7.66.0.

      -Z, --parallel
           Makes curl perform its transfers in parallel as compared to the
           regular serial manner.

           Added in 7.66.0.

      --pass <phrase>
           (SSH TLS) Passphrase for the private key

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

      --path-as-is
           Tell curl to not handle sequences of /../ or /./ in the given URL
           path. Normally curl will squash or merge them according to
           standards but with this option set you tell it not to do that.

           Added in 7.42.0.

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

           PEM/DER support:
             7.39.0: OpenSSL, GnuTLS and GSKit
             7.43.0: NSS and wolfSSL
             7.47.0: mbedtls sha256 support:
             7.44.0: OpenSSL, GnuTLS, NSS and wolfSSL
             7.47.0: mbedtls Other SSL backends not supported.

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

      --post301
           (HTTP) Tells curl to respect RFC 7231/6.4.2 and not convert POST
           requests into GET requests when following a 301 redirection. The



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           non-RFC behaviour is ubiquitous in web browsers, so curl does the
           conversion by default to maintain consistency. However, a server
           may require a POST to remain a POST after such a redirection.
           This option is meaningful only when using -L, --location.

           See also --post302 and --post303 and -L, --location. Added in
           7.17.1.

      --post302
           (HTTP) Tells curl to respect RFC 7231/6.4.3 and not convert POST
           requests into GET requests when following a 302 redirection. The
           non-RFC behaviour is ubiquitous in web browsers, so curl does the
           conversion by default to maintain consistency. However, a server
           may require a POST to remain a POST after such a redirection.
           This option is meaningful only when using -L, --location.

           See also --post301 and --post303 and -L, --location. Added in
           7.19.1.

      --post303
           (HTTP) Tells curl to violate RFC 7231/6.4.4 and not convert POST
           requests into GET requests when following 303 redirections. A
           server may require a POST to remain a POST after a 303
           redirection. This option is meaningful only when using -L, --
           location.

           See also --post302 and --post301 and -L, --location. Added in
           7.26.0.

      --preproxy [protocol://]host[:port]
           Use the specified SOCKS proxy before connecting to an HTTP or
           HTTPS -x, --proxy. In such a case curl first connects to the
           SOCKS proxy and then connects (through SOCKS) to the HTTP or
           HTTPS proxy. Hence pre proxy.

           The pre proxy string should be specified with a protocol://
           prefix to specify alternative proxy protocols. Use socks4://,
           socks4a://, socks5:// or socks5h:// to request the specific SOCKS
           version to be used. No protocol specified will make curl default
           to SOCKS4.

           If the port number is not specified in the proxy string, it is
           assumed to be 1080.

           User and password that might be provided in the proxy string are
           URL decoded by curl. This allows you to pass in special
           characters such as @ by using %40 or pass in a colon with %3a.

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



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           Added in 7.52.0.

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

           This progress bar draws a single line of '#' characters across
           the screen and shows a percentage if the transfer size is known.
           For transfers without a known size, there will be space ship (-
           =o=-) that moves back and forth but only while data is being
           transferred, with a set of flying hash sign symbols on top.

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

           Example:

            curl --proto-default https ftp.mozilla.org

           An unknown or unsupported protocol causes error
           CURLE_UNSUPPORTED_PROTOCOL (1).

           This option does not change the default proxy protocol (http).

           Without this option curl would make a guess based on the host,
           see --url for details.

           Added in 7.45.0.

      --proto-redir <protocols>
           Tells curl to limit what protocols it may use on redirect.
           Protocols denied by --proto are not overridden by this option.
           See --proto for how protocols are represented.

           Example, allow only HTTP and HTTPS on redirect:

            curl --proto-redir -all,http,https http://example.com

           By default curl will allow HTTP, HTTPS, FTP and FTPS on redirect
           (7.65.2).  Older versions of curl allowed all protocols on
           redirect except several disabled for security reasons: Since
           7.19.4 FILE and SCP are disabled, and since 7.40.0 SMB and SMBS
           are also disabled. Specifying all or +all enables all protocols
           on redirect, including those disabled for security.

           Added in 7.20.2.

      --proto <protocols>
           Tells curl to limit what protocols it may use in the transfer.



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           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.

      See also --proto-redir and --proto-default. Added in 7.20.2.

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

           See also -x, --proxy and --proxy-basic and --proxy-digest. Added
           in 7.13.2.

      --proxy-basic
           Tells curl to use HTTP Basic authentication when communicating
           with the given proxy. Use --basic for enabling HTTP Basic with a
           remote host. Basic is the default authentication method curl uses
           with proxies.




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           See also -x, --proxy and --proxy-anyauth and --proxy-digest.

      --proxy-cacert <file>
           Same as --cacert but used in HTTPS proxy context.

           See also --proxy-capath and --cacert and --capath and -x, --
           proxy. Added in 7.52.0.

      --proxy-capath <dir>
           Same as --capath but used in HTTPS proxy context.

           See also --proxy-cacert and -x, --proxy and --capath. Added in
           7.52.0.

      --proxy-cert-type <type>
           Same as --cert-type but used in HTTPS proxy context.

           Added in 7.52.0.

      --proxy-cert <cert[:passwd]>
           Same as -E, --cert but used in HTTPS proxy context.

           Added in 7.52.0.

      --proxy-ciphers <list>
           Same as --ciphers but used in HTTPS proxy context.

           Added in 7.52.0.

      --proxy-crlfile <file>
           Same as --crlfile but used in HTTPS proxy context.

           Added in 7.52.0.

      --proxy-digest
           Tells curl to use HTTP Digest authentication when communicating
           with the given proxy. Use --digest for enabling HTTP Digest with
           a remote host.

           See also -x, --proxy and --proxy-anyauth and --proxy-basic.

      --proxy-header <header/@file>
           (HTTP) Extra header to include in the request when sending HTTP
           to a proxy. You may specify any number of extra headers. This is
           the equivalent option to -H, --header but is for proxy
           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.




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           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.

           Starting in 7.55.0, this option can take an argument in @filename
           style, which then adds a header for each line in the input file.
           Using @- will make curl read the header file from stdin.

           This option can be used multiple times to add/replace/remove
           multiple headers.

           Added in 7.37.0.

      --proxy-insecure
           Same as -k, --insecure but used in HTTPS proxy context.

           Added in 7.52.0.

      --proxy-key-type <type>
           Same as --key-type but used in HTTPS proxy context.

           Added in 7.52.0.

      --proxy-key <key>
           Same as --key but used in HTTPS proxy context.

      --proxy-negotiate
           Tells curl to use HTTP Negotiate (SPNEGO) authentication when
           communicating with the given proxy. Use --negotiate for enabling
           HTTP Negotiate (SPNEGO) with a remote host.

           See also --proxy-anyauth and --proxy-basic. Added in 7.17.1.

      --proxy-ntlm
           Tells curl to use HTTP NTLM authentication when communicating
           with the given proxy. Use --ntlm for enabling NTLM with a remote
           host.

           See also --proxy-negotiate and --proxy-anyauth.

      --proxy-pass <phrase>
           Same as --pass but used in HTTPS proxy context.

           Added in 7.52.0.




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

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

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

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

           Added in 7.43.0.

      --proxy-ssl-allow-beast
           Same as --ssl-allow-beast but used in HTTPS proxy context.

           Added in 7.52.0.

      --proxy-tls13-ciphers <ciphersuite list>
           (TLS) Specifies which cipher suites to use in the connection to
           your HTTPS proxy when it negotiates TLS 1.3. The list of ciphers
           suites must specify valid ciphers. Read up on TLS 1.3 cipher
           suite details on this URL:

            https://curl.haxx.se/docs/ssl-ciphers.html

           This option is currently used only when curl is built to use
           OpenSSL 1.1.1 or later. If you are using a different SSL backend
           you can try setting TLS 1.3 cipher suites by using the --proxy-
           ciphers option.

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

      --proxy-tlsauthtype <type>
           Same as --tlsauthtype but used in HTTPS proxy context.

           Added in 7.52.0.

      --proxy-tlspassword <string>
           Same as --tlspassword but used in HTTPS proxy context.

           Added in 7.52.0.



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      --proxy-tlsuser <name>
           Same as --tlsuser but used in HTTPS proxy context.

           Added in 7.52.0.

      --proxy-tlsv1
           Same as -1, --tlsv1 but used in HTTPS proxy context.

           Added in 7.52.0.

      -U, --proxy-user <user:password>
           Specify the user name and password to use for proxy
           authentication.

           If you use a Windows SSPI-enabled curl binary and do either
           Negotiate or NTLM authentication then you can tell curl to select
           the user name and password from your environment by specifying a
           single colon with this option: "-U :".

           On systems where it works, curl will hide the given option
           argument from process listings. This is not enough to protect
           credentials from possibly getting seen by other users on the same
           system as they will still be visible for a brief moment before
           cleared. Such sensitive data should be retrieved from a file
           instead or similar and never used in clear text in a command
           line.

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

      -x, --proxy [protocol://]host[:port]
           Use the specified proxy.

           The proxy string can be specified with a protocol:// prefix. No
           protocol specified or http:// will be treated as HTTP proxy. Use
           socks4://, socks4a://, socks5:// or socks5h:// to request a
           specific SOCKS version to be used.  (The protocol support was
           added in curl 7.21.7)

           HTTPS proxy support via https:// protocol prefix was added in
           7.52.0 for OpenSSL, GnuTLS and NSS.

           Unrecognized and unsupported proxy protocols cause an error since
           7.52.0.  Prior versions may ignore the protocol and use http://
           instead.

           If the port number is not specified in the proxy string, it is
           assumed to be 1080.

           This option overrides existing environment variables that set the



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           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.

      --proxy1.0 <host[:port]>
           Use the specified HTTP 1.0 proxy. If the port number is not
           specified, it is assumed at port 1080.

           The only difference between this and the HTTP proxy option -x,
           --proxy, is that attempts to use CONNECT through the proxy will
           specify an HTTP 1.0 protocol instead of the default HTTP 1.1.

      -p, --proxytunnel
           When an HTTP proxy is used -x, --proxy, this option will make
           curl tunnel through the proxy. 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.

           To suppress proxy CONNECT response headers when curl is set to
           output headers use --suppress-connect-headers.

           See also -x, --proxy.

      --pubkey <key>
           (SFTP SCP) Public key file name. Allows you to provide your
           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



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           higher that is itself linked against OpenSSL.)

      -Q, --quote
           (FTP SFTP) Send an arbitrary command to the remote FTP or SFTP
           server. Quote commands are sent BEFORE the transfer takes place
           (just after the initial PWD command in an FTP transfer, to be
           exact). To make commands take place after a successful transfer,
           prefix them with a dash '-'.  To make commands be sent after curl
           has changed the working directory, just before the transfer
           command(s), prefix the command with a '+' (this is only supported
           for FTP). You may specify any number of commands.

           If the server returns failure for one of the commands, the entire
           operation will be aborted. You must send syntactically correct
           FTP commands as RFC 959 defines to FTP servers, or one of the
           commands listed below to SFTP servers.

           Prefix the command with an asterisk (*) to make curl continue
           even if the command fails as by default curl will stop at first
           failure.

           This option can be used multiple times.

           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



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                The mkdir command creates the directory named by the
                directory_name operand.

           pwd  The pwd command returns the absolute pathname of the current
                working directory.

           rename source target
                The rename command renames the file or directory named by
                the source operand to the destination path named by the
                target operand.

           rm file
                The rm command removes the file specified by the file
                operand.

           rmdir directory
                The rmdir command removes the directory entry specified by
                the directory operand, provided it is empty.

           symlink source_file target_file
                See ln.

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

      -r, --range <range>
           (HTTP FTP SFTP FILE) Retrieve a byte range (i.e. a partial
           document) from an HTTP/1.1, FTP or SFTP server or a local FILE.
           Ranges can be specified in a number of ways.

           0-499     specifies the first 500 bytes

           500-999   specifies the second 500 bytes

           -500      specifies the last 500 bytes

           9500-     specifies the bytes from offset 9500 and forward

           0-0,-1    specifies the first and last byte only(*)(HTTP)

           100-199,500-599
                     specifies two separate 100-byte ranges(*) (HTTP)

           (*) = NOTE that this will cause the server to reply with a
           multipart response!

           Only digit characters (0-9) are valid in the 'start' and 'stop'



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           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.

      --raw
           (HTTP) When used, it disables all internal HTTP decoding of
           content or transfer encodings and instead makes them passed on
           unaltered, raw.

           Added in 7.16.2.

      -e, --referer <URL>
           (HTTP) Sends the "Referrer Page" information to the HTTP server.
           This can also be set with the -H, --header flag of course.  When
           used with -L, --location you can append ";auto" to the -e, --
           referer URL to make curl automatically set the previous URL when
           it follows a Location: header. The ";auto" string can be used
           alone, even if you don't set an initial -e, --referer.

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

           See also -A, --user-agent and -H, --header.

      -J, --remote-header-name
           (HTTP) This option tells the -O, --remote-name option to use the
           server-specified Content-Disposition filename instead of
           extracting a filename from the URL.

           If the server specifies a file name and a file with that name
           already exists in the current working directory it will not be
           overwritten and an error will occur. If the server doesn't
           specify a file name then this option has no effect.

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

           WARNING: Exercise judicious use of this option, especially on
           Windows. A rogue server could send you the name of a DLL or other



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           file that could possibly be loaded automatically by Windows or
           some third party software.

      --remote-name-all
           This option changes the default action for all given URLs to be
           dealt with as if -O, --remote-name were used for each one. So if
           you want to disable that for a specific URL after --remote-name-
           all has been used, you must use "-o -" or --no-remote-name.

           Added in 7.19.0.

      -O, --remote-name
           Write output to a local file named like the remote file we get.
           (Only the file part of the remote file is used, the path is cut
           off.)

           The file will be saved in the current working directory. If you
           want the file saved in a different directory, make sure you
           change the current working directory before invoking curl with
           this option.

           The remote file name to use for saving is extracted from the
           given URL, nothing else, and if it already exists it will be
           overwritten. If you want the server to be able to choose the file
           name refer to -J, --remote-header-name which can be used in
           addition to this option. If the server chooses a file name and
           that name already exists it will not be overwritten.

           There is no URL decoding done on the file name. If it has %20 or
           other URL encoded parts of the name, they will end up as-is as
           file name.

           You may use this option as many times as the number of URLs you
           have.

      -R, --remote-time
           When used, this will make curl attempt to figure out the
           timestamp of the remote file, and if that is available make the
           local file get that same timestamp.

      --request-target
           (HTTP) Tells curl to use an alternative "target" (path) instead
           of using the path as provided in the URL. Particularly useful
           when wanting to issue HTTP requests without leading slash or
           other data that doesn't follow the regular URL pattern, like
           "OPTIONS *".

           Added in 7.55.0.




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      -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, --request will be used for all
           requests, which if you for example use -L, --location may cause
           unintended side-effects when curl doesn't change request method
           according to the HTTP 30x response codes - and similar.

           (FTP) Specifies a custom FTP command to use instead of LIST when
           doing file lists with FTP.

           (POP3) Specifies a custom POP3 command to use instead of LIST or
           RETR. (Added in 7.26.0)

           (IMAP) Specifies a custom IMAP command to use instead of LIST.
           (Added in 7.30.0)

           (SMTP) Specifies a custom SMTP command to use instead of HELP or
           VRFY. (Added in 7.34.0)

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

      --resolve <host:port:addr[,addr]...>
           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.

           By specifying '*' as host you can tell curl to resolve any host
           and specific port pair to the specified address. Wildcard is



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           resolved last so any --resolve with a specific host and port will
           be used first.

           The provided address set by this option will be used even if -4,
           --ipv4 or -6, --ipv6 is set to make curl use another IP version.

           Support for providing the IP address within [brackets] was added
           in 7.57.0.

           Support for providing multiple IP addresses per entry was added
           in 7.59.0.

           Support for resolving with wildcard was added in 7.64.0.

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

           Added in 7.21.3.

      --retry-all-errors
           Retry on any error. This option is used together with --retry.

           This option is the "sledgehammer" of retrying. Do not use this
           option by default (eg in curlrc), there may be unintended
           consequences such as sending or receiving duplicate data. Do not
           use with redirected input or output. You'd be much better off
           handling your unique problems in shell script. Please read the
           example below.

           Warning: For server compatibility curl attempts to retry failed
           flaky transfers as close as possible to how they were started,
           but this is not possible with redirected input or output. For
           example, before retrying it removes output data from a failed
           partial transfer that was written to an output file. However this
           is not true of data redirected to a | pipe or > file, which are
           not reset. We strongly suggest don't parse or record output via
           redirect in combination with this option, since you may receive
           duplicate data.

           Added in 7.71.0.

      --retry-connrefused
           In addition to the other conditions, consider ECONNREFUSED as a
           transient error too for --retry. This option is used together
           with --retry.

           Added in 7.52.0.

      --retry-delay <seconds>



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           Make curl sleep this amount of time before each retry when a
           transfer has failed with a transient error (it changes the
           default backoff time algorithm between retries). This option is
           only interesting if --retry is also used. Setting this delay to
           zero will make curl use the default backoff time.

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

           Added in 7.12.3.

      --retry-max-time <seconds>
           The retry timer is reset before the first transfer attempt.
           Retries will be done as usual (see --retry) as long as the timer
           hasn't reached this given limit. Notice that if the timer hasn't
           reached the limit, the request will be made and while performing,
           it may take longer than this given time period. To limit a single
           request's maximum time, use -m, --max-time.  Set this option to
           zero to not timeout retries.

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

           Added in 7.12.3.

      --retry <num>
           If a transient error is returned when curl tries to perform a
           transfer, it will retry this number of times before giving up.
           Setting the number to 0 makes curl do no retries (which is the
           default). Transient error means either: a timeout, an FTP 4xx
           response code or an HTTP 408 or 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.

           Since curl 7.66.0, curl will comply with the Retry-After:
           response header if one was present to know when to issue the next
           retry.

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

           Added in 7.12.3.

      --sasl-authzid <identity>
           Use this authorisation identity (authzid), during SASL PLAIN
           authentication, in addition to the authentication identity
           (authcid) as specified by -u, --user.



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           If the option isn't specified, the server will derive the authzid
           from the authcid, but if specified, and depending on the server
           implementation, it may be used to access another user's inbox,
           that the user has been granted access to, or a shared mailbox for
           example.

           Added in 7.66.0.

      --sasl-ir
           Enable initial response in SASL authentication.

           Added in 7.31.0.

      --service-name <name>
           This option allows you to change the service name for SPNEGO.

           Examples: --negotiate --service-name sockd would use
           sockd/server-name.

           Added in 7.43.0.

      -S, --show-error
           When used with -s, --silent, it makes curl show an error message
           if it fails.

      -s, --silent
           Silent or quiet mode. Don't show progress meter or error
           messages.  Makes Curl mute. It will still output the data you ask
           for, potentially even to the terminal/stdout unless you redirect
           it.

           Use -S, --show-error in addition to this option to disable
           progress meter but still show error messages.

           See also -v, --verbose and --stderr.

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

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

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

           Since 7.52.0, --preproxy can be used to specify a SOCKS proxy at
           the same time -x, --proxy is used with an HTTP/HTTPS proxy. In
           such a case curl first connects to the SOCKS proxy and then



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           connects (through SOCKS) to the HTTP or HTTPS proxy.

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

           Added in 7.15.2.

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

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

           Since 7.21.7, this option is superfluous since you can specify a
           socks4a proxy with -x, --proxy using a socks4a:// protocol
           prefix.

           Since 7.52.0, --preproxy can be used to specify a SOCKS proxy at
           the same time -x, --proxy is used with an HTTP/HTTPS proxy. In
           such a case curl first connects to the SOCKS proxy and then
           connects (through SOCKS) to the HTTP or HTTPS proxy.

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

           Added in 7.18.0.

      --socks5-basic
           Tells curl to use username/password authentication when
           connecting to a SOCKS5 proxy.  The username/password
           authentication is enabled by default.  Use --socks5-gssapi to
           force GSS-API authentication to SOCKS5 proxies.

           Added in 7.55.0.

      --socks5-gssapi-nec
           As part of the GSS-API negotiation a protection mode is
           negotiated. RFC 1961 says in section 4.3/4.4 it should be
           protected, but the NEC reference implementation does not.  The
           option --socks5-gssapi-nec allows the unprotected exchange of the
           protection mode negotiation.

           Added in 7.19.4.

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

           Examples: --socks5 proxy-name --socks5-gssapi-service sockd would
           use sockd/proxy-name --socks5 proxy-name --socks5-gssapi-service



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           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
           Tells curl to use GSS-API authentication when connecting to a
           SOCKS5 proxy.  The GSS-API authentication is enabled by default
           (if curl is compiled with GSS-API support).  Use --socks5-basic
           to force username/password authentication to SOCKS5 proxies.

           Added in 7.55.0.

      --socks5-hostname <host[:port]>
           Use the specified SOCKS5 proxy (and let the proxy resolve the
           host name). If the port number is not specified, it is assumed at
           port 1080.

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

           Since 7.21.7, this option is superfluous since you can specify a
           socks5 hostname proxy with -x, --proxy using a socks5h://
           protocol prefix.

           Since 7.52.0, --preproxy can be used to specify a SOCKS proxy at
           the same time -x, --proxy is used with an HTTP/HTTPS proxy. In
           such a case curl first connects to the SOCKS proxy and then
           connects (through SOCKS) to the HTTP or HTTPS proxy.

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

           Added in 7.18.0.

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

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

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

           Since 7.52.0, --preproxy can be used to specify a SOCKS proxy at
           the same time -x, --proxy is used with an HTTP/HTTPS proxy. In
           such a case curl first connects to the SOCKS proxy and then
           connects (through SOCKS) to the HTTP or HTTPS proxy.



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

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

           Added in 7.18.0.

      -Y, --speed-limit <speed>
           If a download is slower than this given speed (in bytes per
           second) for speed-time seconds it gets aborted. speed-time is set
           with -y, --speed-time and is 30 if not set.

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

      -y, --speed-time <seconds>
           If a download is slower than speed-limit bytes per second during
           a speed-time period, the download gets aborted. If speed-time is
           used, the default speed-limit will be 1 unless set with -Y, --
           speed-limit.

           This option controls transfers and thus will not affect slow
           connects etc. If this is a concern for you, try the --connect-
           timeout option.

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

      --ssl-allow-beast
           This option tells curl to not work around a security flaw in the
           SSL3 and TLS1.0 protocols known as BEAST.  If this option isn't
           used, the SSL layer may use workarounds known to cause
           interoperability problems with some older SSL implementations.
           WARNING: this option loosens the SSL security, and by using this
           flag you ask for exactly that.

           Added in 7.25.0.

      --ssl-no-revoke
           (Schannel) This option tells curl to disable certificate
           revocation checks.  WARNING: this option loosens the SSL
           security, and by using this flag you ask for exactly that.

           Added in 7.44.0.

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

           This option was formerly known as --ftp-ssl-reqd.




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           Added in 7.20.0.

      --ssl-revoke-best-effort
           (Schannel) This option tells curl to ignore certificate
           revocation checks when they failed due to missing/offline
           distribution points for the revocation check lists.

           Added in 7.70.0.

      --ssl
           (FTP IMAP POP3 SMTP) Try to use SSL/TLS for the connection.
           Reverts to a non-secure connection if the server doesn't support
           SSL/TLS.  See also --ftp-ssl-control and --ssl-reqd for different
           levels of encryption required.

           This option was formerly known as --ftp-ssl (Added in 7.11.0).
           That option name can still be used but will be removed in a
           future version.

           Added in 7.20.0.

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

           See also --http1.1 and --http2. -2, --sslv2 requires that the
           underlying libcurl was built to support TLS. This option
           overrides -3, --sslv3 and -1, --tlsv1 and --tlsv1.1 and --
           tlsv1.2.

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

           See also --http1.1 and --http2. -3, --sslv3 requires that the
           underlying libcurl was built to support TLS. This option
           overrides -2, --sslv2 and -1, --tlsv1 and --tlsv1.1 and --
           tlsv1.2.

      --stderr
           Redirect all writes to stderr to the specified file instead. If
           the file name is a plain '-', it is instead written to stdout.

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

           See also -v, --verbose and -s, --silent.




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      --styled-output
           Enables the automatic use of bold font styles when writing HTTP
           headers to the terminal. Use --no-styled-output to switch them
           off.

           Added in 7.61.0.

      --suppress-connect-headers
           When -p, --proxytunnel is used and a CONNECT request is made
           don't output proxy CONNECT response headers. This option is meant
           to be used with -D, --dump-header or -i, --include which are used
           to show protocol headers in the output. It has no effect on debug
           options such as -v, --verbose or --trace, or any statistics.

           See also -D, --dump-header and -i, --include and -p, --
           proxytunnel.

      --tcp-fastopen
           Enable use of TCP Fast Open (RFC7413).

           Added in 7.49.0.

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

           Since 7.50.2, curl sets this option by default and you need to
           explicitly switch it off if you don't want it on.

           Added in 7.11.2.

      -t, --telnet-option <opt=val>
           Pass options to the telnet protocol. Supported options are:

           TTYPE=<term> Sets the terminal type.

           XDISPLOC=<X display> Sets the X display location.

           NEW_ENV=<var,val> Sets an environment variable.

      --tftp-blksize <value>
           (TFTP) Set TFTP BLKSIZE option (must be >512). This is the block
           size that curl will try to use when transferring data to or from
           a TFTP server. By default 512 bytes will be used.

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

           Added in 7.20.0.




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      --tftp-no-options
           (TFTP) Tells curl not to send TFTP options requests.

           This option improves interop with some legacy servers that do not
           acknowledge or properly implement TFTP options. When this option
           is used --tftp-blksize is ignored.

           Added in 7.48.0.

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

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

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

      --tls-max <VERSION>
           (SSL) VERSION defines maximum supported TLS version. The minimum
           acceptable version is set by tlsv1.0, tlsv1.1, tlsv1.2 or
           tlsv1.3.


           default
                Use up to recommended TLS version.

           1.0  Use up to TLSv1.0.

           1.1  Use up to TLSv1.1.

           1.2  Use up to TLSv1.2.

           1.3  Use up to TLSv1.3.

      See also --tlsv1.0 and --tlsv1.1 and --tlsv1.2 and --tlsv1.3. --tls-
      max requires that the underlying libcurl was built to support TLS.
      Added in 7.54.0.

      --tls13-ciphers <ciphersuite list>
           (TLS) Specifies which cipher suites to use in the connection if
           it negotiates TLS 1.3. The list of ciphers suites must specify
           valid ciphers. Read up on TLS 1.3 cipher suite details on this



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           URL:

            https://curl.haxx.se/docs/ssl-ciphers.html

           This option is currently used only when curl is built to use
           OpenSSL 1.1.1 or later. If you are using a different SSL backend
           you can try setting TLS 1.3 cipher suites by using the --ciphers
           option.

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

      --tlsauthtype <type>
           Set TLS authentication type. Currently, the only supported option
           is "SRP", for TLS-SRP (RFC 5054). If --tlsuser and --tlspassword
           are specified but --tlsauthtype is not, then this option defaults
           to "SRP".  This option works only if the underlying libcurl is
           built with TLS-SRP support, which requires OpenSSL or GnuTLS with
           TLS-SRP support.

           Added in 7.21.4.

      --tlspassword
           Set password for use with the TLS authentication method specified
           with --tlsauthtype. Requires that --tlsuser also be set.

           This doesn't work with TLS 1.3.

           Added in 7.21.4.

      --tlsuser <name>
           Set username for use with the TLS authentication method specified
           with --tlsauthtype. Requires that --tlspassword also is set.

           This doesn't work with TLS 1.3.

           Added in 7.21.4.

      --tlsv1.0
           (TLS) Forces curl to use TLS version 1.0 or later when connecting
           to a remote TLS server.

           In old versions of curl this option was documented to allow
           _only_ TLS 1.0, but behavior was inconsistent depending on the
           TLS library. Use --tls-max if you want to set a maximum TLS
           version.

           Added in 7.34.0.

      --tlsv1.1



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           (TLS) Forces curl to use TLS version 1.1 or later when connecting
           to a remote TLS server.

           In old versions of curl this option was documented to allow
           _only_ TLS 1.1, but behavior was inconsistent depending on the
           TLS library. Use --tls-max if you want to set a maximum TLS
           version.

           Added in 7.34.0.

      --tlsv1.2
           (TLS) Forces curl to use TLS version 1.2 or later when connecting
           to a remote TLS server.

           In old versions of curl this option was documented to allow
           _only_ TLS 1.2, but behavior was inconsistent depending on the
           TLS library. Use --tls-max if you want to set a maximum TLS
           version.

           Added in 7.34.0.

      --tlsv1.3
           (TLS) Forces curl to use TLS version 1.3 or later when connecting
           to a remote TLS server.

           Note that TLS 1.3 is only supported by a subset of TLS backends.
           At the time of this writing, they are BoringSSL, NSS, and Secure
           Transport (on iOS 11 or later, and macOS 10.13 or later).

           Added in 7.52.0.

      -1, --tlsv1
           (SSL) Tells curl to use at least TLS version 1.x when negotiating
           with a remote TLS server. That means TLS version 1.0 or higher

           See also --http1.1 and --http2. -1, --tlsv1 requires that the
           underlying libcurl was built to support TLS. This option
           overrides --tlsv1.1 and --tlsv1.2 and --tlsv1.3.

      --tr-encoding
           (HTTP) Request a compressed Transfer-Encoding response using one
           of the algorithms curl supports, and uncompress the data while
           receiving it.

           Added in 7.21.6.

      --trace-ascii <file>
           Enables a full trace dump of all incoming and outgoing data,
           including descriptive information, to the given output file. Use



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           "-" as filename to have the output sent to stdout.

           This is very similar to --trace, but leaves out the hex part and
           only shows the ASCII part of the dump. It makes smaller output
           that might be easier to read for untrained humans.

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

           This option overrides --trace and -v, --verbose.

      --trace-time
           Prepends a time stamp to each trace or verbose line that curl
           displays.

           Added in 7.14.0.

      --trace <file>
           Enables a full trace dump of all incoming and outgoing data,
           including descriptive information, to the given output file. Use
           "-" as filename to have the output sent to stdout. Use "%" as
           filename to have the output sent to stderr.

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

           This option overrides -v, --verbose and --trace-ascii.

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

           Added in 7.40.0.

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

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

           You can specify one -T, --upload-file for each URL on the command
           line. Each -T, --upload-file + URL pair specifies what to upload



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           and to where. curl also supports "globbing" of the -T, --upload-
           file argument, meaning that you can upload multiple files to a
           single URL by using the same URL globbing style supported in the
           URL, like this:

            curl --upload-file "{file1,file2}" http://www.example.com

           or even

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

           When uploading to an SMTP server: the uploaded data is assumed to
           be RFC 5322 formatted. It has to feature the necessary set of
           headers and mail body formatted correctly by the user as curl
           will not transcode nor encode it further in any way.

      --url <url>
           Specify a URL to fetch. This option is mostly handy when you want
           to specify URL(s) in a config file.

           If the given URL is missing a scheme name (such as "http://" or
           "ftp://" etc) then curl will make a guess based on the host. If
           the outermost sub-domain name matches DICT, FTP, IMAP, LDAP, POP3
           or SMTP then that protocol will be used, otherwise HTTP will be
           used. Since 7.45.0 guessing can be disabled by setting a default
           protocol, see --proto-default for details.

           This option may be used any number of times. To control where
           this URL is written, use the -o, --output or the -O, --remote-
           name options.

           Warning: On Windows, particular file:// accesses can be converted
           to network accesses by the operating system. Beware!

      -B, --use-ascii
           (FTP LDAP) Enable ASCII transfer. For FTP, this can also be
           enforced by using a URL that ends with ";type=A". This option
           causes data sent to stdout to be in text mode for win32 systems.

      -A, --user-agent <name>
           (HTTP) Specify the User-Agent string to send to the HTTP server.
           To encode blanks in the string, surround the string with single
           quote marks. This header can also be set with the -H, --header or
           the --proxy-header options.

           If you give an empty argument to -A, --user-agent (""), it will
           remove the header completely from the request. If you prefer a
           blank header, you can set it to a single space (" ").




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

      -u, --user <user:password>
           Specify the user name and password to use for server
           authentication. Overrides -n, --netrc and --netrc-optional.

           If you simply specify the user name, curl will prompt for a
           password.

           The user name and passwords are split up on the first colon,
           which makes it impossible to use a colon in the user name with
           this option. The password can, still.

           On systems where it works, curl will hide the given option
           argument from process listings. This is not enough to protect
           credentials from possibly getting seen by other users on the same
           system as they will still be visible for a brief moment before
           cleared. Such sensitive data should be retrieved from a file
           instead or similar and never used in clear text in a command
           line.

           When using Kerberos V5 with a Windows based server you should
           include the Windows domain name in the user name, in order for
           the server to successfully obtain a Kerberos Ticket. If you don't
           then the initial authentication handshake may fail.

           When using NTLM, the user name can be specified simply as the
           user name, without the domain, if there is a single domain and
           forest in your setup for example.

           To specify the domain name use either Down-Level Logon Name or
           UPN (User Principal Name) formats. For example, EXAMPLE\user and
           user@example.com respectively.

           If you use a Windows SSPI-enabled curl binary and perform
           Kerberos V5, Negotiate, NTLM or Digest authentication then you
           can tell curl to select the user name and password from your
           environment by specifying a single colon with this option: "-u
           :".

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

      -v, --verbose
           Makes curl verbose during the operation. Useful for debugging and
           seeing what's going on "under the hood". A line starting with '>'
           means "header data" sent by curl, '<' means "header data"
           received by curl that is hidden in normal cases, and a line
           starting with '*' means additional info provided by curl.




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           If you only want HTTP headers in the output, -i, --include might
           be the option you're looking for.

           If you think this option still doesn't give you enough details,
           consider using --trace or --trace-ascii instead.

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

           See also -i, --include. This option overrides --trace and --
           trace-ascii.

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

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

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

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

           alt-svc
                Support for the Alt-Svc: header is provided.

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

           brotli
                Support for automatic brotli compression over HTTP(S).

           CharConv
                curl was built with support for character set conversions
                (like EBCDIC)

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

           GSS-API
                GSS-API is supported.

           HTTP2
                HTTP/2 support has been built-in.




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           HTTP3
                HTTP/3 support has been built-in.

           HTTPS-proxy
                This curl is built to support HTTPS proxy.

           IDN  This curl supports IDN - international domain names.

           IPv6 You can use IPv6 with this.

           krb4 Krb4 for FTP is supported.

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

           libz Automatic decompression of compressed files over HTTP is
                supported.

           Metalink
                This curl supports Metalink

           MultiSSL
                This curl supports multiple TLS backends.

           NTLM NTLM authentication is supported.

           NTLM NTLM authentication is supported.

           PSL  PSL is short for Public Suffix List and means that this curl
                has been built with knowledge about "public suffixes".

           SPNEGO
                SPNEGO authentication is supported.

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

           SSPI SSPI is supported.

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

           UnixSockets
                Unix sockets support is provided.

      -w, --write-out <format>
           Make curl display information on stdout after a completed



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           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.

           The output will be written to standard output, but this can be
           switched to standard error by using %{stderr}.

           NOTE: The %-symbol is a special symbol in the win32-environment,
           where all occurrences of % must be doubled when using this
           option.

           The variables available are:

           content_type   The Content-Type of the requested document, if
                          there was any.

           filename_effective
                          The ultimate filename that curl writes out to.
                          This is only meaningful if curl is told to write
                          to a file with the -O, --remote-name or -o, --
                          output option. It's most useful in combination
                          with the -J, --remote-header-name option. (Added
                          in 7.26.0)

           ftp_entry_path The initial path curl ended up in when logging on
                          to the remote FTP server. (Added in 7.15.4)

           http_code      The numerical response code that was found in the
                          last retrieved HTTP(S) or FTP(s) transfer. In
                          7.18.2 the alias response_code was added to show
                          the same info.

           http_connect   The numerical code that was found in the last
                          response (from a proxy) to a curl CONNECT request.
                          (Added in 7.12.4)

           http_version   The http version that was effectively used. (Added
                          in 7.50.0)

           json           A JSON object with all available keys.




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           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)

           proxy_ssl_verify_result
                          The result of the HTTPS proxy's SSL peer
                          certificate verification that was requested. 0
                          means the verification was successful. (Added in
                          7.52.0)

           redirect_url   When an HTTP request was made without -L, --
                          location to follow redirects (or when --max-redir
                          is met), this variable will show the actual URL a
                          redirect would have gone 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)

           response_code  The numerical response code that was found in the
                          last transfer (formerly known as "http_code").
                          (Added in 7.18.2)

           scheme         The URL scheme (sometimes called protocol) that
                          was effectively used (Added in 7.52.0)

           size_download  The total amount of bytes that were downloaded.

           size_header    The total amount of bytes of the downloaded
                          headers.

           size_request   The total amount of bytes that were sent in the
                          HTTP request.

           size_upload    The total amount of bytes that were uploaded.

           speed_download The average download speed that curl measured for



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                          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)

           stderr         From this point on, the -w, --write-out output
                          will be written to standard error. (Added in
                          7.63.0)

           stdout         From this point on, the -w, --write-out output
                          will be written to standard output.  This is the
                          default, but can be used to switch back after
                          switching to stderr.  (Added in 7.63.0)

           time_appconnect
                          The time, in seconds, it took from the start until
                          the SSL/SSH/etc connect/handshake to the remote
                          host was 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 including 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.



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                          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.

           url_effective  The URL that was fetched last. This is most
                          meaningful if you've told curl to follow location:
                          headers.

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

      --xattr
           When saving output to a file, this option tells curl to store
           certain file metadata in extended file attributes. Currently, the
           URL is stored in the xdg.origin.url attribute and, for HTTP, the
           content type is stored in the mime_type attribute. If the file
           system does not support extended attributes, a warning is issued.

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

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

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


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

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

      [url-protocol]_PROXY [protocol://]<host>[:port]
           Sets the proxy server to use for [url-protocol], where the
           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/domains>
           list of host names that shouldn't go through any proxy. If set to



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           an asterisk '*' only, it matches all hosts. Each name in this
           list is matched as either a domain name which contains the
           hostname, or the hostname itself.

           This environment variable disables use of the proxy even when
           specified with the -x, --proxy option. That is
           NO_PROXY=direct.example.com curl -x http://proxy.example.com
           http://direct.example.com accesses the target URL directly, and
           NO_PROXY=direct.example.com curl -x http://proxy.example.com
           http://somewhere.example.com accesses the target URL through the
           proxy.

           The list of host names can also be include numerical IP
           addresses, and IPv6 versions should then be given without
           enclosing brackets.

      CURL_SSL_BACKEND <TLS backend>
           If curl was built with support for "MultiSSL", meaning that it
           has built-in support for more than one TLS backend, this
           environment variable can be set to the case insensitive name of
           the particular backend to use when curl is invokved. Setting a
           name that isn't a built-in alternative, will make curl stay with
           the default.

      QLOGDIR <directory name>
           If curl was built with HTTP/3 support, setting this environment
           variable to a local directory will make curl produce qlogs in
           that directory, using file names named after the destination
           connection id (in hex). Do note that these files can become
           rather large. Works with both QUIC backends.

      SSLKEYLOGFILE <file name>
           If you set this environment variable to a file name, curl will
           store TLS secrets from its connections in that file when invoked
           to enable you to analyze the TLS traffic in real time using
           network analyzing tools such as Wireshark. This works with the
           following TLS backends: OpenSSL, libressl, BoringSSL, GnuTLS, NSS
           and wolfSSL.

 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:




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      http://
           Makes it use it as an HTTP proxy. The default if no scheme prefix
           is used.

      https://
           Makes it treated as an HTTPS proxy.

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

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

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

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

 EXIT CODES
      There are a bunch of different error codes and their corresponding
      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    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.



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      10   FTP accept failed. While waiting for the server to connect back
           when an active FTP session is used, an error code was sent over
           the control connection or similar.

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

      12   During an active FTP session while waiting for the server to
           connect back to curl, the timeout expired.

      13   FTP weird PASV reply, Curl 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.

      16   HTTP/2 error. A problem was detected in the HTTP2 framing layer.
           This is somewhat generic and can be one out of several problems,
           see the error message for details.

      17   FTP 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.



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      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   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.



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      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.



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      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

      91   Invalid SSL certificate status.

      92   Stream error in HTTP/2 framing layer.

      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
      https://curl.haxx.se

 SEE ALSO
      ftp(1), wget(1)















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