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curl(1)                           Curl Manual                          curl(1)




NAME

       curl - transfer a URL


SYNOPSIS

       curl [options] [URL...]


DESCRIPTION

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

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

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


URL

       The  URL  syntax is protocol-dependent. You'll find a detailed descrip-
       tion in RFC 3986.

       You can specify multiple URLs or parts of URLs  by  writing  part  sets
       within braces as in:

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

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

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

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

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

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

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

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

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

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

         http://www.letters.com/file[a-z:2].txt

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

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

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

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

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

       curl will attempt to re-use connections for multiple file transfers, so
       that  getting many files from the same server will not do multiple con-
       nects / handshakes. This improves speed. Of course this is only done on
       files  specified  on  a  single command line and cannot be used between
       separate curl invokes.


PROGRESS METER

       curl normally displays a progress meter during  operations,  indicating
       the  amount  of  transferred  data,  transfer speeds and estimated time
       left, etc.

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

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

       It  is not the same case for FTP upload as that operation does not spit
       out any response data to the terminal.

       If you prefer a progress "bar" instead of the regular meter, -# is your
       friend.


OPTIONS

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

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

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

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

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

       -:, --next
              Tells curl to use a separate operation for the following URL and
              associated  options.  This  allows  you  to  send  several   URL
              requests,  each  with  their  own specific options, for example,
              such as different user names or custom requests for each. (Added
              in 7.36.0)

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

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

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

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

              (Added in 7.36.0)

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

              (Added in 7.36.0)

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

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

       -3, --sslv3
              (SSL) Forces curl to use SSL version 3 when negotiating  with  a
              remote  SSL  server.  Sometimes curl is built without SSLv3 sup-
              port.

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

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

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

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

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

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

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

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

              If no '=' symbol is used in the line, it is treated as  a  file-
              name  to  use to read previously stored cookie lines from, which
              should be used in this session if they match. Using this  method
              also  activates  the "cookie parser" which will make curl record
              incoming cookies too, which may be handy if you're using this in
              combination  with  the -L, --location option. The file format of
              the file to read cookies from should be plain  HTTP  headers  or
              the Netscape/Mozilla cookie file format.

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

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

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

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

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

              See also --proxy-basic.

       -c, --cookie-jar <file name>
              (HTTP)  Specify to which file you want curl to write all cookies
              after a completed operation. Curl writes all cookies  previously
              read  from a specified file as well as all cookies received from
              remote server(s). If no cookies are known, no data will be writ-
              ten.  The  file  will  be written using the Netscape cookie file
              format. If you set the file name to  a  single  dash,  "-",  the
              cookies will be written to stdout.

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

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

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

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

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

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

       --ciphers <list of ciphers>
              (SSL) Specifies which ciphers to use in the connection. The list
              of  ciphers  must  specify  valid ciphers. Read up on SSL cipher
              list          details           on           this           URL:
              https://www.openssl.org/docs/apps/ciphers.html

              NSS  ciphers  are  done differently than OpenSSL and GnuTLS. The
              full list of NSS ciphers is in the NSSCipherSuite entry at  this
              URL:                                         https://git.fedora-
              hosted.org/cgit/mod_nss.git/plain/docs/mod_nss.html#Directives

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

       --compressed
              (HTTP) Request a compressed response using one of the algorithms
              curl supports, and save  the  uncompressed  document.   If  this
              option  is  used  and  the server sends an unsupported encoding,
              curl will report an error.

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

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

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

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

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

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

              (SMTP added in 7.40.0)

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

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

              (Added in 7.19.7)

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

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

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

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

       -D, --dump-header <file>
              Write the protocol headers to the specified file.

              This option is handy to use when you want to store  the  headers
              that  an  HTTP site sends to you. Cookies from the headers could
              then be read in a  second  curl  invocation  by  using  the  -b,
              --cookie  option! The -c, --cookie-jar option is a better way to
              store cookies.

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

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

       --data-ascii <data>
              See -d, --data.

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

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

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

       --data-raw <data>
              (HTTP)  This posts data similarly to --data but without the spe-
              cial interpretation of the @ character. See -d, --data.   (Added
              in 7.43.0)

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

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

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

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

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

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

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

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

              none   Don't allow any delegation.

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

              always Unconditionally allow the server to delegate.

       --digest
              (HTTP) Enables HTTP Digest authentication. This is an  authenti-
              cation  scheme  that  prevents the password from being sent over
              the wire in clear text. Use this in combination with the  normal
              -u,  --user  option  to  set  user  name  and password. See also
              --ntlm, --negotiate and --anyauth for related options.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       -E, --cert <certificate[:password]>
              (SSL)  Tells  curl  to use the specified client certificate file
              when getting a file with HTTPS, FTPS or another SSL-based proto-
              col.  The  certificate must be in PKCS#12 format if using Secure
              Transport, or PEM format if using  any  other  engine.   If  the
              optional password isn't specified, it will be queried for on the
              terminal. Note that this option  assumes  a  "certificate"  file
              that  is  the  private  key and the private certificate concate-
              nated! See --cert and --key to specify them independently.

              If curl is built against the NSS SSL library  then  this  option
              can  tell curl the nickname of the certificate to use within the
              NSS database defined by the environment variable SSL_DIR (or  by
              default  /etc/pki/nssdb).  If  the  NSS PEM PKCS#11 module (lib-
              nsspem.so) is available then PEM files may  be  loaded.  If  you
              want to use a file from the current directory, please precede it
              with "./" prefix, in order to avoid confusion with  a  nickname.
              If  the nickname contains ":", it needs to be preceded by "\" so
              that it is not recognized as password delimiter.  If  the  nick-
              name  contains "\", it needs to be escaped as "\\" so that it is
              not recognized as an escape character.

              (iOS and Mac OS X only) If curl is built against  Secure  Trans-
              port,  then  the  certificate string can either be the name of a
              certificate/private key in the system or user keychain,  or  the
              path  to  a  PKCS#12-encoded certificate and private key. If you
              want to use a file from the current directory, please precede it
              with "./" prefix, in order to avoid confusion with a nickname.

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

       --engine <name>
              Select the OpenSSL crypto engine to use for  cipher  operations.
              Use  --engine  list  to  print  a  list  of build-time supported
              engines. Note that not all (or  none)  of  the  engines  may  be
              available at run-time.

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

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

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

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

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

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

              The windows version of curl will automatically  look  for  a  CA
              certs file named 'curl-ca-bundle.crt', either in the same direc-
              tory as curl.exe, or in the Current Working Directory, or in any
              folder along your PATH.

              If  curl  is  built  against  the  NSS  SSL library, the NSS PEM
              PKCS#11 module (libnsspem.so) needs to  be  available  for  this
              option to work properly.

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

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

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

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

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

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

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

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

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

              This  is  currently  only implemented in the OpenSSL, GnuTLS and
              NSS backends.  (Added in 7.41.0)

       --false-start

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

              This  is currently only implemented in the NSS and Secure Trans-
              port (on iOS 7.0 or later, or OS  X  10.9  or  later)  backends.
              (Added in 7.42.0)

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

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

       -F, --form <name=content>
              (HTTP) This lets curl emulate a filled-in form in which  a  user
              has  pressed  the  submit  button. This causes curl to POST data
              using the  Content-Type  multipart/form-data  according  to  RFC
              2388.  This  enables uploading of binary files etc. To force the
              'content' part to be a file, prefix the  file  name  with  an  @
              sign.  To just get the content part from a file, prefix the file
              name with the symbol <. The difference between @ and <  is  then
              that  @  makes a file get attached in the post as a file upload,
              while the < makes a text field and just  get  the  contents  for
              that text field from a file.

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

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

              To read content from stdin instead of a file, use - as the file-
              name. This goes for both @ and <  constructs.  Unfortunately  it
              does  not support reading the file from a named pipe or similar,
              as it needs the full size before the transfer starts.

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

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

              or

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

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

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

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

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

              or

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

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

              See further examples and details in the MANUAL.

              This option can be used multiple times.

       --ftp-account [data]
              (FTP) When an FTP server asks for "account data" after user name
              and password has been provided, this data is sent off using  the
              ACCT command. (Added in 7.13.0)

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

       --ftp-alternative-to-user <command>
              (FTP) If authenticating with the USER and PASS  commands  fails,
              send  this  command.   When  connecting  to  Tumbleweed's Secure
              Transport server over FTPS using  a  client  certificate,  using
              "SITE  AUTH"  will tell the server to retrieve the username from
              the certificate. (Added in 7.15.5)

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

       --ftp-method [method]
              (FTP)  Control what method curl should use to reach a file on an
              FTP(S) server. The method argument should be one of the  follow-
              ing alternatives:

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

              nocwd  curl does no CWD at all. curl will do  SIZE,  RETR,  STOR
                     etc and give a full path to the server for all these com-
                     mands. This is the fastest behavior.

              singlecwd
                     curl does one CWD with the full target directory and then
                     operates  on  the  file  "normally" (like in the multicwd
                     case). This is somewhat  more  standards  compliant  than
                     'nocwd' but without the full penalty of 'multicwd'.

              (Added in 7.15.1)

       --ftp-pasv
              (FTP)  Use  passive mode for the data connection. Passive is the
              internal default behavior, but using this option can be used  to
              override a previous -P/-ftp-port option. (Added in 7.11.0)

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

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

       --ftp-skip-pasv-ip
              (FTP) Tell curl to not use the IP address the server suggests in
              its  response to curl's PASV command when curl connects the data
              connection. Instead curl will re-use  the  same  IP  address  it
              already uses for the control connection. (Added in 7.14.2)

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

       --ftp-pret
              (FTP) Tell curl to send a PRET command before PASV  (and  EPSV).
              Certain  FTP  servers,  mainly drftpd, require this non-standard
              command for directory listings as well as up  and  downloads  in
              PASV mode.  (Added in 7.20.x)

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

       --ftp-ssl-ccc-mode [active/passive]
              (FTP)  Use  CCC  (Clear  Command Channel) Sets the CCC mode. The
              passive mode will not initiate the shutdown,  but  instead  wait
              for the server to do it, and will not reply to the shutdown from
              the server. The active mode initiates the shutdown and waits for
              a reply from the server.  (Added in 7.16.2)

       --ftp-ssl-control
              (FTP)  Require  SSL/TLS  for  the FTP login, clear for transfer.
              Allows secure authentication, but non-encrypted  data  transfers
              for  efficiency.   Fails the transfer if the server doesn't sup-
              port SSL/TLS.  (Added in 7.16.0) that can still be used but will
              be removed in a future version.

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

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

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

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

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

       -H, --header <header>
              (HTTP)  Extra header to include in the request when sending HTTP
              to a server. You may specify any number of extra  headers.  Note
              that if you should add a custom header that has the same name as
              one of the internal ones curl would  use,  your  externally  set
              header will be used instead of the internal one. This allows you
              to make even trickier stuff than curl  would  normally  do.  You
              should  not  replace internally set headers without knowing per-
              fectly well what you're doing. Remove an internal header by giv-
              ing  a  replacement  without  content  on  the right side of the
              colon, as in: -H "Host:". If you send the custom header with no-
              value  then its header must be terminated with a semicolon, such
              as -H "X-Custom-Header;" to send "X-Custom-Header:".

              curl will make sure that each header  you  add/replace  is  sent
              with the proper end-of-line marker, you should thus not add that
              as a part of the header content: do not add newlines or carriage
              returns, they will only mess things up for you.

              See also the -A, --user-agent and -e, --referer options.

              Starting in 7.37.0, you need --proxy-header to send custom head-
              ers intended for a proxy.

              Example:

              # curl -H "X-First-Name: Joe" http://192.168.0.1/

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

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

       --hostpubmd5 <md5>
              (SCP/SFTP)  Pass  a string containing 32 hexadecimal digits. The
              string should be the 128 bit MD5 checksum of the  remote  host's
              public key, curl will refuse the connection with the host unless
              the md5sums match. (Added in 7.17.1)

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

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

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

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

               curl --interface eth0:1 http://www.netscape.com/

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

       -j, --junk-session-cookies
              (HTTP) When curl is told to read cookies from a given file, this
              option  will  make  it  discard all "session cookies". This will
              basically have the same effect as if a new session  is  started.
              Typical  browsers  always  discard  session cookies when they're
              closed down.

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

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

       -k, --insecure
              (SSL) This option explicitly allows curl to  perform  "insecure"
              SSL connections and transfers. All SSL connections are attempted
              to be made secure by using the CA certificate  bundle  installed
              by  default.  This  makes  all connections considered "insecure"
              fail unless -k, --insecure is used.

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

       -K, --config <config file>
              Specify  which config file to read curl arguments from. The con-
              fig file is a text file in which command line arguments  can  be
              written  which  then will be used as if they were written on the
              actual command line.

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

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

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

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

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

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

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

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

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

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

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

       --keepalive-time <seconds>
              This  option  sets  the  time  a connection needs to remain idle
              before sending keepalive probes and the time between  individual
              keepalive probes. It is currently effective on operating systems
              offering  the  TCP_KEEPIDLE  and  TCP_KEEPINTVL  socket  options
              (meaning  Linux, recent AIX, HP-UX and more). This option has no
              effect if --no-keepalive is used. (Added in 7.18.0)

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

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

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

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

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

       --krb <level>
              (FTP) Enable Kerberos authentication and use. The level must  be
              entered and should be one of 'clear', 'safe', 'confidential', or
              'private'. Should you use a level that  is  not  one  of  these,
              'private' will instead be used.

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

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

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

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

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

              Note:  When  combined  with -X, --request <command>, this option
              can be used to send an UIDL command instead, so the user may use
              the  email's  unique  identifier  rather than it's message id to
              make the request. (Added in 7.21.5)

       -L, --location
              (HTTP/HTTPS) If the server reports that the requested  page  has
              moved to a different location (indicated with a Location: header
              and a 3XX response code), this option will make  curl  redo  the
              request on the new place. If used together with -i, --include or
              -I, --head, headers from all requested pages will be shown. When
              authentication  is  used, curl only sends its credentials to the
              initial host. If a redirect takes curl to a different  host,  it
              won't  be  able to intercept the user+password. See also --loca-
              tion-trusted on how to change this. You can limit the amount  of
              redirects to follow by using the --max-redirs option.

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

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

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

              If  this  option is used several times, the last given file name
              will be used. (Added in 7.16.1)

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

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

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

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

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

       --local-port <num>[-num]
              Set a preferred number or range of local port numbers to use for
              the  connection(s).   Note  that  port  numbers  by nature are a
              scarce resource that will be busy at times so setting this range
              to something too narrow might cause unnecessary connection setup
              failures. (Added in 7.15.2)

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

       -m, --max-time <seconds>
              Maximum time in seconds that you allow the  whole  operation  to
              take.   This is useful for preventing your batch jobs from hang-
              ing for hours due to slow networks or links going  down.   Since
              7.32.0, this option accepts decimal values, but the actual time-
              out will decrease in accuracy as the specified timeout increases
              in decimal precision.  See also the --connect-timeout option.

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

       --login-options <options>
              Specify the login options to use during server authentication.

              You can use the  login  options  to  specify  protocol  specific
              options  that may be used during authentication. At present only
              IMAP, POP3 and SMTP support login options. For more  information
              about  the  login options please see RFC 2384, RFC 5092 and IETF
              draft draft-earhart-url-smtp-00.txt (Added in 7.34.0).

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

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

              (Added in 7.25.0)

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

              (Added in 7.20.0)

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

              NOTE: The file size is not always known prior to  download,  and
              for such files this option has no effect even if the file trans-
              fer ends up being larger than this given  limit.  This  concerns
              both FTP and HTTP transfers.

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

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

              When  performing  an  address  verification  (VRFY command), the
              recipient should be specified as the user name or user name  and
              domain (as per Section 3.5 of RFC5321). (Added in 7.34.0)

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

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

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

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

              Example to use a remote Metalink file:

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

              To use a Metalink file in the local file system, use FILE proto-
              col (file://):

              curl --metalink file://example.metalink

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

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

       -n, --netrc
              Makes  curl  scan  the  .netrc  (_netrc  on Windows) file in the
              user's home directory for login name and password. This is typi-
              cally  used for FTP on Unix. If used with HTTP, curl will enable
              user authentication. See netrc(5) ftp(1) for details on the file
              format.  Curl  will  not  complain if that file doesn't have the
              right permissions (it should not be either world- or group-read-
              able).  The environment variable "HOME" is used to find the home
              directory.

              A quick and very simple example of how  to  setup  a  .netrc  to
              allow  curl to FTP to the machine host.domain.com with user name
              'myself' and password 'secret' should look similar to:

              machine host.domain.com login myself password secret

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

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

       --netrc-file
              This  option  is similar to --netrc, except that you provide the
              path (absolute or relative) to the netrc file that  Curl  should
              use.   You  can  only  specify one netrc file per invocation. If
              several --netrc-file options are provided,  only  the  last  one
              will be used.  (Added in 7.21.5)

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


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


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

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

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

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

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

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

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

       --no-sessionid
              (SSL)  Disable curl's use of SSL session-ID caching.  By default
              all transfers are done using the cache. Note that while  nothing
              should  ever  get  hurt  by attempting to reuse SSL session-IDs,
              there seem to be broken SSL implementations in the wild that may
              require  you to disable this in order for you to succeed. (Added
              in 7.16.0)

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

       --noproxy <no-proxy-list>
              Comma-separated  list  of hosts which do not use a proxy, if one
              is specified.  The only wildcard is a single * character,  which
              matches all hosts, and effectively disables the proxy. Each name
              in this list is matched as either a domain  which  contains  the
              hostname,  or  the hostname itself. For example, local.com would
              match  local.com,  local.com:80,  and  www.local.com,  but   not
              www.notlocal.com.  (Added in 7.19.4).

       --ntlm (HTTP)  Enables  NTLM  authentication.  The  NTLM authentication
              method was designed by Microsoft and is used by IIS web servers.
              It  is a proprietary protocol, reverse-engineered by clever peo-
              ple and implemented in curl based on their efforts. This kind of
              behavior  should  not be endorsed, you should encourage everyone
              who uses NTLM to switch to a public and  documented  authentica-
              tion method instead, such as Digest.

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

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

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

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

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

              or use several variables like:

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

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

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

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

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

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

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

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

       --oauth2-bearer
              (IMAP, POP3, SMTP) Specify the Bearer Token for OAUTH 2.0 server
              authentication. The Bearer Token is used in conjunction with the
              user  name  which  can  be specified as part of the --url or -u,
              --user options.

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

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

       --proxy-header <header>
              (HTTP) Extra header to include in the request when sending  HTTP
              to a proxy. You may specify any number of extra headers. This is
              the equivalent option to -H, --header but is for proxy  communi-
              cation  only  like  in CONNECT requests when you want a separate
              header sent to the proxy to what is sent to  the  actual  remote
              host.

              curl  will  make  sure  that each header you add/replace is sent
              with the proper end-of-line marker, you should thus not add that
              as a part of the header content: do not add newlines or carriage
              returns, they will only mess things up for you.

              Headers specified with this  option  will  not  be  included  in
              requests that curl knows will not be sent to a proxy.

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

              (Added in 7.37.0)

       -p, --proxytunnel
              When an HTTP proxy is used (-x, --proxy), this option will cause
              non-HTTP  protocols  to  attempt  to  tunnel  through  the proxy
              instead of merely using it to do HTTP-like operations. The  tun-
              nel  approach  is  made  with the HTTP proxy CONNECT request and
              requires that the proxy allows direct connect to the remote port
              number curl wants to tunnel through to.

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

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

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

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

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

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

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

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

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

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

              (Added in 7.42.0)

       --post301
              (HTTP) Tells curl to respect RFC  2616/10.3.2  and  not  convert
              POST  requests  into GET requests when following a 301 redirect-
              ion. The non-RFC behaviour is ubiquitous  in  web  browsers,  so
              curl  does  the  conversion  by default to maintain consistency.
              However, a server may require a POST to remain a POST after such
              a  redirection.  This  option  is meaningful only when using -L,
              --location (Added in 7.17.1)

       --post302
              (HTTP) Tells curl to respect RFC  2616/10.3.2  and  not  convert
              POST  requests  into GET requests when following a 302 redirect-
              ion. The non-RFC behaviour is ubiquitous  in  web  browsers,  so
              curl  does  the  conversion  by default to maintain consistency.
              However, a server may require a POST to remain a POST after such
              a  redirection.  This  option  is meaningful only when using -L,
              --location (Added in 7.19.1)

       --post303
              (HTTP) Tells curl to respect RFC  2616/10.3.2  and  not  convert
              POST  requests  into GET requests when following a 303 redirect-
              ion. The non-RFC behaviour is ubiquitous  in  web  browsers,  so
              curl  does  the  conversion  by default to maintain consistency.
              However, a server may require a POST to remain a POST after such
              a  redirection.  This  option  is meaningful only when using -L,
              --location (Added in 7.26.0)

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

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

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

              =  Permit  only this protocol (ignoring the list already permit-
                 ted), though subject  to  later  modification  by  subsequent
                 entries in the comma separated list.

              For example:

              --proto -ftps  uses the default protocols, but disables ftps

              --proto -all,https,+http
                             only enables http and https

              --proto =http,https
                             also only enables http and https

              Unknown  protocols  produce  a  warning.  This allows scripts to
              safely rely on being able to disable potentially dangerous  pro-
              tocols,  without  relying  upon  support for that protocol being
              built into curl to avoid an error.

              This option can be used multiple times, in which case the effect
              is  the same as concatenating the protocols into one instance of
              the option.

              (Added in 7.20.2)

       --proto-redir <protocols>
              Tells curl to use the listed protocols  after  a  redirect.  See
              --proto for how protocols are represented.

              (Added in 7.20.2)

       --proxy-anyauth
              Tells  curl to pick a suitable authentication method when commu-
              nicating with  the  given  proxy.  This  might  cause  an  extra
              request/response round-trip. (Added in 7.13.2)

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

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

       --proxy-negotiate
              Tells curl to use HTTP Negotiate  (SPNEGO)  authentication  when
              communicating with the given proxy. Use --negotiate for enabling
              HTTP Negotiate (SPNEGO) with a remote host. (Added in 7.17.1)

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

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

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

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

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

       --pubkey <key>
              (SSH)  Public  key  file name. Allows you to provide your public
              key in this separate file.

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

              (As of 7.39.0, curl attempts to automatically extract the public
              key from the private key file, so passing this option is  gener-
              ally not required. Note that this public key extraction requires
              libcurl to be linked against a copy of libssh2 1.2.8  or  higher
              that is itself linked against OpenSSL.)

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

       -Q, --quote <command>
              (FTP/SFTP)  Send  an arbitrary command to the remote FTP or SFTP
              server. Quote commands are sent BEFORE the transfer takes  place
              (just  after  the  initial PWD command in an FTP transfer, to be
              exact). To make commands take place after a successful transfer,
              prefix  them  with  a  dash '-'.  To make commands be sent after
              curl has changed the working directory, just before the transfer
              command(s),  prefix  the  command  with a '+' (this is only sup-
              ported for FTP). You may specify any number of commands. If  the
              server returns failure for one of the commands, the entire oper-
              ation will be aborted. You must send syntactically  correct  FTP
              commands  as  RFC 959 defines to FTP servers, or one of the com-
              mands listed below to SFTP servers.  This  option  can  be  used
              multiple  times. When speaking to an FTP server, prefix the com-
              mand with an asterisk (*) to make curl continue even if the com-
              mand fails as by default curl will stop at first failure.

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

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

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

              chown user file
                     The chown command sets the owner of the file named by the
                     file  operand  to the user ID specified by the user oper-
                     and. The user operand is a decimal integer user ID.

              ln source_file target_file
                     The ln and symlink commands create a symbolic link at the
                     target_file  location  pointing  to the source_file loca-
                     tion.

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

              pwd    The pwd command returns the absolute pathname of the cur-
                     rent working directory.

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

              rm file
                     The rm command removes the file specified by the file op-
                     erand.

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

              symlink source_file target_file
                     See ln.

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

              0-499     specifies the first 500 bytes

              500-999   specifies the second 500 bytes

              -500      specifies the last 500 bytes

              9500-     specifies the bytes from offset 9500 and forward

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

              500-700,600-799
                        specifies 300 bytes from offset 500(H)

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

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

              Only  digit characters (0-9) are valid in the 'start' and 'stop'
              fields of the 'start-stop' range syntax. If a non-digit  charac-
              ter is given in the range, the server's response will be unspec-
              ified, depending on the server's configuration.

              You should also be aware that many HTTP/1.1 servers do not  have
              this  feature  enabled, so that when you attempt to get a range,
              you'll instead get the whole document.

              FTP and SFTP range downloads only  support  the  simple  'start-
              stop'  syntax  (optionally with one of the numbers omitted). FTP
              use depends on the extended FTP command SIZE.

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

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

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

       --raw  (HTTP) When used, it disables all internal HTTP decoding of con-
              tent or transfer encodings and  instead  makes  them  passed  on
              unaltered, raw. (Added in 7.16.2)

       --remote-name-all
              This  option changes the default action for all given URLs to be
              dealt with as if -O, --remote-name were used for each one. So if
              you want to disable that for a specific URL after --remote-name-
              all has been used, you must  use  "-o  -"  or  --no-remote-name.
              (Added in 7.19.0)

       --resolve <host:port:address>
              Provide  a  custom  address  for  a specific host and port pair.
              Using this, you can make the curl requests(s)  use  a  specified
              address  and  prevent the otherwise normally resolved address to
              be used. Consider it a sort of /etc/hosts  alternative  provided
              on  the  command line. The port number should be the number used
              for the specific protocol the host will be used  for.  It  means
              you  need several entries if you want to provide address for the
              same host but different ports.

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

              (Added in 7.21.3)

       --retry <num>
              If  a  transient  error is returned when curl tries to perform a
              transfer, it will retry this number of times before  giving  up.
              Setting  the  number to 0 makes curl do no retries (which is the
              default). Transient error means either: a timeout,  an  FTP  4xx
              response code or an HTTP 5xx response code.

              When  curl  is about to retry a transfer, it will first wait one
              second and then for all forthcoming retries it will  double  the
              waiting  time until it reaches 10 minutes which then will be the
              delay between the rest of the retries.  By  using  --retry-delay
              you   disable  this  exponential  backoff  algorithm.  See  also
              --retry-max-time to limit the total time  allowed  for  retries.
              (Added in 7.12.3)

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

       --retry-delay <seconds>
              Make curl sleep this amount of time before  each  retry  when  a
              transfer  has  failed  with  a  transient  error (it changes the
              default backoff time algorithm between retries). This option  is
              only  interesting if --retry is also used. Setting this delay to
              zero will make curl use the default  backoff  time.   (Added  in
              7.12.3)

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

       --retry-max-time <seconds>
              The retry timer is reset  before  the  first  transfer  attempt.
              Retries will be done as usual (see --retry) as long as the timer
              hasn't reached this given limit. Notice that if the timer hasn't
              reached  the  limit, the request will be made and while perform-
              ing, it may take longer than this given time period. To limit  a
              single  request's  maximum  time,  use -m, --max-time.  Set this
              option to zero to not timeout retries. (Added in 7.12.3)

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

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

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

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

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

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

       --ssl  (FTP,  POP3,  IMAP, SMTP) Try to use SSL/TLS for the connection.
              Reverts to a non-secure connection if the server doesn't support
              SSL/TLS.   See also --ftp-ssl-control and --ssl-reqd for differ-
              ent levels of encryption required. (Added in 7.20.0)

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

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

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

       --ssl-allow-beast
              (SSL) This option tells curl to not work around a security  flaw
              in the SSL3 and TLS1.0 protocols known as BEAST.  If this option
              isn't used, the SSL layer may use  workarounds  known  to  cause
              interoperability  problems  with some older SSL implementations.
              WARNING: this option loosens the SSL security, and by using this
              flag you ask for exactly that.  (Added in 7.25.0)

       --ssl-no-revoke
              (WinSSL)  This  option tells curl to disable certificate revoca-
              tion checks.  WARNING: this option loosens the SSL security, and
              by using this flag you ask for exactly that.  (Added in 7.44.0)

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

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

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

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

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

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

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

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

       --socks5-hostname <host[:port]>
              Use  the  specified  SOCKS5 proxy (and let the proxy resolve the
              host name). If the port number is not specified, it  is  assumed
              at port 1080. (Added in 7.18.0)

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

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

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

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

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

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

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

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

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

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

       --socks5-gssapi-nec
              As  part of the GSS-API negotiation a protection mode is negoti-
              ated. RFC 1961 says in section 4.3/4.4 it should  be  protected,
              but  the  NEC  reference  implementation  does  not.  The option
              --socks5-gssapi-nec allows the unprotected exchange of the  pro-
              tection mode negotiation. (Added in 7.19.4).

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

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

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

              TTYPE=<term> Sets the terminal type.

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

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

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

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

              You can specify one -T for each URL on the command line. Each -T
              + URL pair specifies what to upload and to where. curl also sup-
              ports "globbing" of the -T argument, meaning that you can upload
              multiple  files  to  a single URL by using the same URL globbing
              style supported in the URL, like this:

              curl -T "{file1,file2}" http://www.uploadtothissite.com

              or even

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

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

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

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

              (Added in 7.20.0)

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

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

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

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

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

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

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

              (Added in 7.21.6)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       -w, --write-out <format>
              Make curl display information on stdout after a completed trans-
              fer. The format is a string that may contain  plain  text  mixed
              with  any  number of variables. The format can be specified as a
              literal "string", or you can have curl read the  format  from  a
              file  with  "@filename" and to tell curl to read the format from
              stdin you write "@-".

              The variables present in the output format will  be  substituted
              by  the  value or text that curl thinks fit, as described below.
              All variables are specified as %{variable_name} and to output  a
              normal  % you just write them as %%. You can output a newline by
              using \n, a carriage return with \r and a tab space with \t.

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

              The variables available are:

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

              filename_effective
                             The  ultimate  filename  that curl writes out to.
                             This is only meaningful if curl is told to  write
                             to  a  file  with  the  --remote-name or --output
                             option. It's most useful in combination with  the
                             --remote-header-name option. (Added in 7.25.1)

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

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

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

              local_ip       The  IP  address  of  the  local  end of the most
                             recently done connection - can be either IPv4  or
                             IPv6 (Added in 7.29.0)

              local_port     The  local  port number of the most recently done
                             connection (Added in 7.29.0)

              num_connects   Number of new connects made in the recent  trans-
                             fer. (Added in 7.12.3)

              num_redirects  Number  of  redirects  that  were followed in the
                             request. (Added in 7.12.3)

              redirect_url   When an HTTP request was made without -L to  fol-
                             low redirects, this variable will show the actual
                             URL a redirect  would  take  you  to.  (Added  in
                             7.18.2)

              remote_ip      The  remote  IP address of the most recently done
                             connection - can be either IPv4 or IPv6 (Added in
                             7.29.0)

              remote_port    The  remote port number of the most recently done
                             connection (Added in 7.29.0)

              size_download  The total amount of bytes that were downloaded.

              size_header    The total amount of bytes of the downloaded head-
                             ers.

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

              size_upload    The total amount of bytes that were uploaded.

              speed_download The average download speed that curl measured for
                             the complete download. Bytes per second.

              speed_upload   The  average  upload speed that curl measured for
                             the complete upload. Bytes per second.

              ssl_verify_result
                             The result of the SSL peer certificate  verifica-
                             tion that was requested. 0 means the verification
                             was successful. (Added in 7.19.0)

              time_appconnect
                             The time, in seconds,  it  took  from  the  start
                             until  the  SSL/SSH/etc  connect/handshake to the
                             remote host was completed. (Added in 7.19.0)

              time_connect   The time, in seconds,  it  took  from  the  start
                             until  the  TCP  connect  to  the remote host (or
                             proxy) was completed.

              time_namelookup
                             The time, in seconds,  it  took  from  the  start
                             until the name resolving was completed.

              time_pretransfer
                             The  time,  in  seconds,  it  took from the start
                             until the file transfer was just about to  begin.
                             This includes all pre-transfer commands and nego-
                             tiations that are specific to the particular pro-
                             tocol(s) involved.

              time_redirect  The time, in seconds, it took for all redirection
                             steps include name lookup,  connect,  pretransfer
                             and  transfer  before  the  final transaction was
                             started. time_redirect shows the complete  execu-
                             tion  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 trans-
                             ferred. 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  opera-
                             tion lasted. The time will be displayed with mil-
                             lisecond resolution.

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

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

       -x, --proxy <[protocol://][user:password@]proxyhost[:port]>
              Use the specified proxy.

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

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

              This  option  overrides  existing environment variables that set
              the proxy to use. If there's an environment variable  setting  a
              proxy, you can set proxy to "" to override it.

              All operations that are performed over an HTTP proxy will trans-
              parently be converted to HTTP. It means  that  certain  protocol
              specific operations might not be available. This is not the case
              if you can tunnel through the proxy, as one with the -p, --prox-
              ytunnel option.

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

              The  proxy host can be specified the exact same way as the proxy
              environment variables, including the protocol  prefix  (http://)
              and the embedded user + password.

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

       -X, --request <command>
              (HTTP) Specifies a custom request method to use when communicat-
              ing  with the HTTP server.  The specified request method will be
              used instead of the method otherwise  used  (which  defaults  to
              GET).  Read  the HTTP 1.1 specification for details and explana-
              tions. Common additional HTTP requests include PUT  and  DELETE,
              but related technologies like WebDAV offers PROPFIND, COPY, MOVE
              and more.

              Normally you don't need this option. All  sorts  of  GET,  HEAD,
              POST and PUT requests are rather invoked by using dedicated com-
              mand line options.

              This option only changes  the  actual  word  used  in  the  HTTP
              request,  it does not alter the way curl behaves. So for example
              if you want to make a proper HEAD request, using  -X  HEAD  will
              not suffice. You need to use the -I, --head option.

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

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

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

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

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

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

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


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

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

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

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

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

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

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

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

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

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

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

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

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

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

              IPv6   You can use IPv6 with this.

              krb4   Krb4 for FTP is supported.

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

              libz   Automatic  decompression of compressed files over HTTP is
                     supported.

              NTLM   NTLM authentication is supported.

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

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

              SPNEGO SPNEGO authentication is supported.

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

              IDN    This curl supports IDN - international domain names.

              GSS-API
                     GSS-API is supported.

              SSPI   SSPI is supported.

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

              HTTP2  HTTP/2 support has been built-in.

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


FILES

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


ENVIRONMENT

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

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


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

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

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

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

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


PROXY PROTOCOL PREFIXES

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

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

       The supported proxy protocol prefixes are as follows:

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

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

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

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


EXIT CODES

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

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

       2      Failed to initialize.

       3      URL malformed. The syntax was not correct.

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

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

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

       7      Failed to connect to host.

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

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

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

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

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

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

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

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

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

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

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

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

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

       26     Read error. Various reading problems.

       27     Out of memory. A memory allocation request failed.

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

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

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

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

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

       35     SSL connect error. The SSL handshaking failed.

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

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

       38     LDAP cannot bind. LDAP bind operation failed.

       39     LDAP search failed.

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

       42     Aborted by callback. An application told curl to abort the oper-
              ation.

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

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

       47     Too many redirects. When following redirects, curl hit the maxi-
              mum amount.

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

       49     Malformed telnet option.

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

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

       53     SSL crypto engine not found.

       54     Cannot set SSL crypto engine as default.

       55     Failed sending network data.

       56     Failure in receiving network data.

       58     Problem with the local certificate.

       59     Couldn't use specified SSL cipher.

       60     Peer certificate cannot be authenticated with known CA  certifi-
              cates.

       61     Unrecognized transfer encoding.

       62     Invalid LDAP URL.

       63     Maximum file size exceeded.

       64     Requested FTP SSL level failed.

       65     Sending the data requires a rewind that failed.

       66     Failed to initialise SSL Engine.

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

       68     File not found on TFTP server.

       69     Permission problem on TFTP server.

       70     Out of disk space on TFTP server.

       71     Illegal TFTP operation.

       72     Unknown TFTP transfer ID.

       73     File already exists (TFTP).

       74     No such user (TFTP).

       75     Character conversion failed.

       76     Character conversion functions required.

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

       78     The resource referenced in the URL does not exist.

       79     An unspecified error occurred during the SSH session.

       80     Failed to shut down the SSL connection.

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

       83     Issuer check failed (added in 7.19.0).

       84     The FTP PRET command failed

       85     RTSP: mismatch of CSeq numbers

       86     RTSP: mismatch of Session Identifiers

       87     unable to parse FTP file list

       88     FTP chunk callback reported error

       89     No connection available, the session will be queued

       90     SSL public key does not matched pinned public key

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


AUTHORS / CONTRIBUTORS

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


WWW

       http://curl.haxx.se


FTP

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


SEE ALSO

       ftp(1), wget(1)



Curl 7.40.0                       30 Nov 2014                          curl(1)

curl 7.44.0 - Generated Sat Aug 15 19:29:13 CDT 2015
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Individual documents may contain additional copyright information.