curl(1)



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.example.com/file[1-100].txt

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

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

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

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

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

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

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

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

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

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

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

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

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

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

PROGRESS METER
       curl normally displays a progress meter during  operations,  indicating
       the  amount  of  transferred  data,  transfer speeds and estimated time
       left, etc. The progress meter displays number of bytes and  the  speeds
       are  in  bytes per second. The suffixes (k, M, G, T, P) are 1024 based.
       For example 1k is 1024 bytes. 1M is 1048576 bytes.

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

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

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

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

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

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

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

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

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

              Added in 7.53.0.

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

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

              Used together with -u, --user.

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

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

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

              Used together with -u, --user.

              See also --proxy-basic.

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

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

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

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

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

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

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

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

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

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

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

              Added in 7.41.0.

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

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

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

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

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

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

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

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

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

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

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

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

              Added in 7.56.0.

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

       -K, --config <file>

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              See also -m, --max-time.

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

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

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

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

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

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

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

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

              See also -r, --range.

       -c, --cookie-jar <filename>
              (HTTP) Specify to which file you want curl to write all  cookies
              after  a  completed  operation. Curl writes all cookies from its
              in-memory cookie storage to the given file at the end of  opera-
              tions.  If  no  cookies  are known, no data will be written. The
              file will be written using the Netscape cookie file  format.  If
              you set the file name to a single dash, "-", the cookies will be
              written to stdout.

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

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

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

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

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

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

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

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

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

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

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

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

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

              (SMTP added in 7.40.0)

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

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

              Added in 7.19.7.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              none   Don't allow any delegation.

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

              always Unconditionally allow the server to delegate.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              See also -o, --output.

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

              See also --random-file.

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

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

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

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

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

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

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

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

              Added in 7.52.0.

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

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

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

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

              Added in 7.42.0.

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

              See also -F, --form.

       -F, --form <name=content>
              (HTTP SMTP IMAP) For HTTP protocol family, this lets  curl  emu-
              late  a  filled-in  form  in which a user has pressed the submit
              button. This causes curl to POST  data  using  the  Content-Type
              multipart/form-data according to RFC 2388.

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

              This enables uploading of binary files etc. To force  the  'con-
              tent' part to be a file, prefix the file name with an @ sign. To
              just get the content part from a file, prefix the file name with
              the  symbol  <.  The  difference  between @ and < is then that @
              makes a file get attached in the post as a  file  upload,  while
              the < makes a text field and just get the contents for that text
              field from a file.

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

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

              To read content from stdin instead of a file, use - as the file-
              name.  This  goes  for  both @ and < constructs. If stdin is not
              attached to a regular file, it is buffered  first  to  determine
              its  size  and  allow  a possible resend. Defining a part's data
              from a named non-regular file (such as a named pipe or  similar)
              is  unfortunately  not  subject  to buffering and will be effec-
              tively read at transmission time; since the full size is unknown
              before  the  transfer starts, data is sent as chunks by HTTP and
              rejected by IMAP.

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

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

              or

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

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

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

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

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

              or

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

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

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

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

              or

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

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

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

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

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

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

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

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

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

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

              See further examples and details in the MANUAL.

              This option can be used multiple times.

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

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

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

              Added in 7.13.0.

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

              Added in 7.15.5.

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

              See also --create-dirs.

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

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

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

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

       Added in 7.15.1.

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

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

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

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

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

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

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

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

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

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

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

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

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

              Added in 7.20.0.

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

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

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

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

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

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

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

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

              Added in 7.16.0.

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

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

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

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

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

       -H, --header <header/@file>
              (HTTP)  Extra header to include in the request when sending HTTP
              to a server. You may specify any number of extra  headers.  Note
              that if you should add a custom header that has the same name as
              one of the internal ones curl would  use,  your  externally  set
              header will be used instead of the internal one. This allows you
              to make even trickier stuff than curl  would  normally  do.  You
              should  not  replace internally set headers without knowing 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.

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

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

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

              Example:

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

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

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

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

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

              Added in 7.17.1.

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

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

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

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

       --http2-prior-knowledge
              (HTTP)  Tells  curl  to  issue  its  non-TLS HTTP requests using
              HTTP/2 without HTTP/1.1 Upgrade.  It  requires  prior  knowledge
              that  the  server  supports HTTP/2 straight away. HTTPS requests
              will still do HTTP/2 the standard way with  negotiated  protocol
              version in the TLS handshake.

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

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

              See also --no-alpn. --http2 requires that the underlying libcurl
              was built to support HTTP/2. This option overrides --http1.1 and
              -0, --http1.0 and --http2-prior-knowledge. Added in 7.33.0.

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

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

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

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

              See also -v, --verbose.

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

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

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

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

       --interface <name>

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

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

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

              See also --dns-interface.

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

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

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

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

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

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

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

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

              Added in 7.18.0.

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

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

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

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

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

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

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

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

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

              Added in 7.16.1.

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

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

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

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

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

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

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

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

              Added in 7.21.5.

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

              Added in 7.15.2.

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

              See also -u, --user.

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

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

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

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

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

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

              Added in 7.34.0.

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

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

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

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

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

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

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

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

              Added in 7.20.0.

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

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

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

              See also --limit-rate.

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

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

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

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

              See also --connect-timeout.

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

              Example to use a remote Metalink file:

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

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

               curl --metalink file://example.metalink

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              machine host.domain.com login myself password secret

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

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

              For example, you can do both a GET and a POST in a  single  com-
              mand line:

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

              Added in 7.36.0.

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

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

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

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

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

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

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

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

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

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

              Added in 7.16.0.

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

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

              Added in 7.19.4.

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

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

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

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

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

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

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

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

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

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

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

              or use several variables like:

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

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

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

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

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

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

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

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

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

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

              Added in 7.42.0.

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

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

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

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

       --post301
              (HTTP) Tells curl to respect RFC 7231/6.4.2 and not convert POST
              requests into GET requests when following a 301 redirection. The
              non-RFC  behaviour  is  ubiquitous in web browsers, so curl does
              the conversion by default to maintain  consistency.  However,  a
              server  may  require  a POST to remain a POST after such a redi-
              rection. This option is meaningful only when using  -L,  --loca-
              tion.

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

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

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

       --post303
              (HTTP) Tells curl to respect RFC 7231/6.4.4 and not convert POST
              requests into GET requests when following a 303 redirection. The
              non-RFC  behaviour  is  ubiquitous in web browsers, so curl does
              the conversion by default to maintain  consistency.  However,  a
              server  may  require  a POST to remain a POST after such a redi-
              rection. This option is meaningful only when using  -L,  --loca-
              tion.

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

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

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

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

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

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

              Added in 7.52.0.

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

              This  progress  bar draws a single line of '#' characters across
              the screen and shows a percentage if the transfer size is known.
              For  transfers  without a known size, it will instead output one
              '#' character for every 1024 bytes transferred.

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

              Example:

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

              An unknown or unsupported  protocol  causes  error  CURLE_UNSUP-
              PORTED_PROTOCOL (1).

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

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

              Added in 7.45.0.

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

              Example, allow only HTTP and HTTPS on redirect:

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

              By default curl will allow all protocols on redirect except sev-
              eral  disabled  for  security reasons: Since 7.19.4 FILE and SCP
              are disabled, and since 7.40.0 SMB and SMBS are  also  disabled.
              Specifying  all  or  +all  enables  all  protocols  on redirect,
              including those disabled for security.

              Added in 7.20.2.

       --proto <protocols>
              Tells curl to limit what protocols it may use in  the  transfer.
              Protocols  are evaluated left to right, are comma separated, and
              are each a protocol name or

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

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

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

              For example:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

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

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

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

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

              Added in 7.37.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

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

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

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

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

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

              Added in 7.52.0.

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

              Added in 7.43.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              See also -x, --proxy.

       --pubkey <key>
              (SFTP SCP) Public key file name. Allows you to provide your pub-
              lic key in this separate file.

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

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

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

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

              This  option can be used multiple times. When speaking to an FTP
              server, prefix the command with an asterisk  (*)  to  make  curl
              continue  even if the command fails as by default curl will stop
              at first failure.

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

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

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

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

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

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

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

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

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

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

              symlink source_file target_file
                     See ln.

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

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

              0-499     specifies the first 500 bytes

              500-999   specifies the second 500 bytes

              -500      specifies the last 500 bytes

              9500-     specifies the bytes from offset 9500 and forward

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

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

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

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

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

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

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

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

              Added in 7.16.2.

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

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

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

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

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

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

              WARNING: Exercise judicious use of this  option,  especially  on
              Windows.  A  rogue  server  could  send you the name of a DLL or
              other file that could possibly be loaded automatically  by  Win-
              dows or some third party software.

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

              Added in 7.19.0.

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

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

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

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

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

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

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

              Added in 7.55.0.

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

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

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

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

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

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

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

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

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

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

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

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

              Added in 7.21.3.

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

              Added in 7.52.0.

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

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

              Added in 7.12.3.

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

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

              Added in 7.12.3.

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

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

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

              Added in 7.12.3.

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

              Added in 7.31.0.

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

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

              Added in 7.43.0.

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

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

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

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

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

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

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

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

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

              Added in 7.15.2.

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

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

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

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

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

              Added in 7.18.0.

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

              Added in 7.55.0.

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

              Added in 7.19.4.

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

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

              Added in 7.19.4.

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

              Added in 7.55.0.

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

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

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

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

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

              Added in 7.18.0.

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

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

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

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

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

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

              Added in 7.18.0.

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

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

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

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

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

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

              Added in 7.25.0.

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

              Added in 7.44.0.

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

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

              Added in 7.20.0.

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

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

              Added in 7.20.0.

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

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

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

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

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

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

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

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

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

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

              Added in 7.49.0.

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

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

              Added in 7.11.2.

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

              TTYPE=<term> Sets the terminal type.

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

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

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

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

              Added in 7.20.0.

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

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

              Added in 7.48.0.

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

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

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

       --tls-max <VERSION>
              (SSL)  VERSION  defines maximum supported TLS version. A minimum
              is defined by arguments tlsv1.0 or tlsv1.1 or tlsv1.2.

              default
                     Use up to recommended TLS version.

              1.0    Use up to TLSv1.0.

              1.1    Use up to TLSv1.1.

              1.2    Use up to TLSv1.2.

              1.3    Use up to TLSv1.3.

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

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

              Added in 7.21.4.

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

              Added in 7.21.4.

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

              Added in 7.21.4.

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

              Added in 7.34.0.

       --tlsv1.1
              (TLS) Forces curl to use TLS version 1.1 when  connecting  to  a
              remote TLS server.

              Added in 7.34.0.

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

              Added in 7.34.0.

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

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

              Added in 7.52.0.

       -1, --tlsv1
              (SSL)  Tells curl to use TLS version 1.x when negotiating with a
              remote TLS server. That means TLS version 1.0, 1.1 or 1.2.

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

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

              Added in 7.21.6.

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

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

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

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

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

              Added in 7.14.0.

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

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

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

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

              Added in 7.40.0.

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

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

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

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

              or even

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              IPv6   You can use IPv6 with this.

              krb4   Krb4 for FTP is supported.

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

              libz   Automatic decompression of compressed files over HTTP  is
                     supported.

              NTLM   NTLM authentication is supported.

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

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

              SPNEGO SPNEGO authentication is supported.

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

              IDN    This curl supports IDN - international domain names.

              GSS-API
                     GSS-API is supported.

              SSPI   SSPI is supported.

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

              HTTP2  HTTP/2 support has been built-in.

              UnixSockets
                     Unix sockets support is provided.

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

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

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

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

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

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

              The variables available are:

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

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

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

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

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

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

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

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

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

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

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

              redirect_url   When an HTTP request was made without -L, --loca-
                             tion to follow redirects (or when --max-redir  is
                             met),  this  variable  will show the actual URL a
                             redirect would have gone to. (Added in 7.18.2)

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

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

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

              size_download  The total amount of bytes that were downloaded.

              size_header    The total amount of bytes of the downloaded 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 including 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.

              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.

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

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

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

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

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

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

       [url-protocol]_PROXY [protocol://]<host>[:port]
              Sets  the proxy server to use for [url-protocol], where the 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.

              Since  7.53.0,  this environment variable disable the proxy even
              if specify -x, --proxy  option.  That  is  NO_PROXY=direct.exam-
              ple.com  curl  -x  http://proxy.example.com  http://direct.exam-
              ple.com    accesses    the    target    URL    directly,     and
              NO_PROXY=direct.example.com   curl  -x  http://proxy.example.com
              http://somewhere.example.com accesses  the  target  URL  through
              proxy.

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      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.

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

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

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

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

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

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

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

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

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

       19     FTP couldn't download/access the given file, the RETR (or  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     Bad  download resume. Couldn't continue an earlier aborted down-
              load.

       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
       https://curl.haxx.se

SEE ALSO
       ftp(1), wget(1)

Curl 7.56.1                    November 16, 2016                       curl(1)

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