Provided by: curl_7.64.0-2ubuntu1_amd64 bug

NAME

       curl - transfer a URL

SYNOPSIS

       curl [options / URLs]

DESCRIPTION

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

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

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

URL

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

PROGRESS METER

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

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

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

       It  is  not  the same case for FTP upload as that operation does not spit 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 directory as curl.exe, or in the Current
              Working Directory, or in any folder along your PATH.

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

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

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

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

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

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

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

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

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

              Added in 7.41.0.

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

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

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

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

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

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

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

              (Schannel  only)  Client  certificates  must be specified by a path expression to a
              certificate store. (Loading PFX is not supported; you can  import  it  to  a  store
              first).  You  can  use  "<store  location>\<store name>\<thumbprint>" to refer to a
              certificate    in    the    system     certificates     store,     for     example,
              "CurrentUser\MY\934a7ac6f8a5d579285a74fa61e19f23ddfe8d7a".  Thumbprint is usually a
              SHA-1 hex string  which  you  can  see  in  certificate  details.  Following  store
              locations  are  supported:  CurrentUser,  LocalMachine,  CurrentService,  Services,
              CurrentUserGroupPolicy, LocalMachineGroupPolicy, LocalMachineEnterprise.

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

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

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

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

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

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

              Added in 7.56.0.

       --compressed
              (HTTP) Request a compressed response using one of the algorithms curl supports, and
              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 character between
              the option and its parameter.

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

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

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

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

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

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

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

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

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

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

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

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

              See also -m, --max-time.

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

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

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

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

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

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

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

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

              See also -r, --range.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              (SMTP added in 7.40.0)

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

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

              Added in 7.19.7.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              none   Don't allow any delegation.

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

              always Unconditionally allow the server to delegate.

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

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

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

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

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

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

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

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

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

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

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

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

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

              See also --proto. Added in 7.61.0.

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

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

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

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

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

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

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

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

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

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

       -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 operations.  Use  --engine
              list  to  print a list of build-time supported engines. Note that not all (or none)
              of the engines may be available at run-time.

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

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

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

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

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

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

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

              Added in 7.52.0.

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

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

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

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

              Added in 7.42.0.

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

              See also -F, --form.

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

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

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

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

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

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

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

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

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

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

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

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

              or

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

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

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

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

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

              or

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

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

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

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

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

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

              or

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

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

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

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

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

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

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

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

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

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

              See further examples and details in the MANUAL.

              This option can be used multiple times.

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

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

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

              Added in 7.13.0.

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

              Added in 7.15.5.

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

              See also --create-dirs.

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

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

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

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

       Added in 7.15.1.

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

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

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

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

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

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

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

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

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

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

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

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

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

              Added in 7.20.0.

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

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

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

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

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

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

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

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

              Added in 7.16.0.

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

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

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

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

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

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

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

              Added in 7.59.0.

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

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

              Added in 7.60.0.

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

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

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

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

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

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

              Example:

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

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

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

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

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

              Added in 7.17.1.

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

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

              A future curl version will deny continuing if the response isn't at least  HTTP/1.0
              unless this option is used.

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

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

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

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

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

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

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

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

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

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

       -i, --include
              Include the HTTP 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.

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

              See also --dns-interface.

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

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

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

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

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

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

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

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

              Added in 7.18.0.

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

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

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

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

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

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

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

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

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

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

              Added in 7.16.1.

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

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

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

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

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

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

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

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

              Added in 7.21.5.

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

              Added in 7.15.2.

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

              See also -u, --user.

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

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

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

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

              Added in 7.20.0.

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

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

              A  size  modifier  may  be  used.  For example, Appending 'k' or 'K' will count the
              number as kilobytes, 'm' or 'M' makes it megabytes,  while  'g'  or  'G'  makes  it
              gigabytes. Examples: 200K, 3m and 1G. (Added in 7.58.0)

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

              See also --limit-rate.

       --max-redirs <num>
              (HTTP) Set maximum number of redirection-followings allowed. When -L, --location is
              used, is used to  prevent  curl  from  following  redirections  "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 <seconds>
              Maximum time in seconds that you allow the whole operation to take.  This is useful
              for preventing your batch jobs from hanging for hours due to slow networks or links
              going down.  Since 7.32.0, this option  accepts  decimal  values,  but  the  actual
              timeout  will  decrease  in  accuracy as the specified timeout increases in decimal
              precision.

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

              See also --connect-timeout.

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

              Example to use a remote Metalink file:

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

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

               curl --metalink file://example.metalink

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              machine host.domain.com login myself password secret

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

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

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

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

              Added in 7.36.0.

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

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

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

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

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

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

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

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

       --no-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 disabling a proxy, you can set noproxy
              list to "" to override it.

              Added in 7.19.4.

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

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

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

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

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

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

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

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

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

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

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

              or use several variables like:

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

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

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

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

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

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

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

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

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

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

              Added in 7.42.0.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              Added in 7.52.0.

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

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

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

              Example:

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

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

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

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

              Added in 7.45.0.

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

              Example, allow only HTTP and HTTPS on redirect:

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

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

              Added in 7.20.2.

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

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

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

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

              For example:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

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

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

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

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

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

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

              Added in 7.37.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

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

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

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

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

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

              Added in 7.52.0.

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

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

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

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

              Added in 7.43.0.

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

              Added in 7.52.0.

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

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

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

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

              Added in 7.52.0.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              See also -x, --proxy.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              symlink source_file target_file
                     See ln.

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

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

              0-499     specifies the first 500 bytes

              500-999   specifies the second 500 bytes

              -500      specifies the last 500 bytes

              9500-     specifies the bytes from offset 9500 and forward

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

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

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

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

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

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

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

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

              Added in 7.16.2.

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

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

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

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

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

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

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

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

              Added in 7.19.0.

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

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

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

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

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

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

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

              Added in 7.55.0.

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

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

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

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

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

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

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

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

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

       --resolve <host:port:address[,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.

              By specifying '*' as host you can tell curl to resolve any host and  specific  port
              pair  to  the  specified address. Wildcard is resolved last so any --resolve with a
              specific host and port will be used first.

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

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

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

              Support for resolving with wildcard was added in 7.64.0.

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

              Added in 7.21.3.

       --retry-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
              performing, it may take longer than this given  time  period.  To  limit  a  single
              request´s maximum time, use -m, --max-time.  Set this option to zero to not timeout
              retries.

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

              Added in 7.12.3.

       --retry <num>
              If a transient error is returned when curl tries to perform  a  transfer,  it  will
              retry  this number of times before giving up. Setting the number to 0 makes curl do
              no retries (which is the default). Transient error means either: a timeout, an  FTP
              4xx response code or an HTTP 408 or 5xx response code.

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

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

              Added in 7.12.3.

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

              Added in 7.31.0.

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

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

              Added in 7.43.0.

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

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

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

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

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

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

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

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

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

              Added in 7.15.2.

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

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

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

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

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

              Added in 7.18.0.

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

              Added in 7.55.0.

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

              Added in 7.19.4.

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

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

              Added in 7.19.4.

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

              Added in 7.55.0.

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

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

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

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

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

              Added in 7.18.0.

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

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

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

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

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

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

              Added in 7.18.0.

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

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

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

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

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

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

              Added in 7.25.0.

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

              Added in 7.44.0.

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

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

              Added in 7.20.0.

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

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

              Added in 7.20.0.

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

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

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

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

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

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

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

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

              Added in 7.61.0.

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

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

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

              Added in 7.49.0.

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

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

              Added in 7.11.2.

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

              TTYPE=<term> Sets the terminal type.

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

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

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

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

              Added in 7.20.0.

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

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

              Added in 7.48.0.

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

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

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

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

              default
                     Use up to recommended TLS version.

              1.0    Use up to TLSv1.0.

              1.1    Use up to TLSv1.1.

              1.2    Use up to TLSv1.2.

              1.3    Use up to TLSv1.3.

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

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

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

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

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

              Added in 7.21.4.

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

              Added in 7.21.4.

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

              Added in 7.21.4.

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

              Added in 7.34.0.

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

              Added in 7.34.0.

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

              Added in 7.34.0.

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

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

              Added in 7.52.0.

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

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

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

              Added in 7.21.6.

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

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

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

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

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

              Added in 7.14.0.

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

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

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

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

              Added in 7.40.0.

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

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

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

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

              or even

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              IPv6   You can use IPv6 with this.

              krb4   Krb4 for FTP is supported.

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

              libz   Automatic decompression of compressed files over HTTP is supported.

              NTLM   NTLM authentication is supported.

              Debug  This curl uses a libcurl built with Debug. This enables more  error-tracking
                     and memory debugging etc. For curl-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 suffixes".

              MultiSSL
                     This curl supports multiple TLS backends.

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

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

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

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

              The variables available are:

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

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

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

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

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

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

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

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

              num_connects   Number  of  new  connects  made  in  the  recent transfer. (Added in
                             7.12.3)

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

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

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

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

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

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

              size_download  The total amount of bytes that were downloaded.

              size_header    The total amount of bytes of the downloaded headers.

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

              size_upload    The total amount of bytes that were uploaded.

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

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

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

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

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

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

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

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

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

              time_redirect  The time, in seconds, it took for all  redirection  steps  including
                             name  lookup,  connect,  pretransfer  and  transfer before the final
                             transaction was started. time_redirect shows the complete  execution
                             time for multiple redirections. (Added in 7.12.3)

              time_starttransfer
                             The  time,  in  seconds, it took from the start until the first byte
                             was just about to be transferred. This includes time_pretransfer and
                             also the time the server needed to calculate the result.

              time_total     The total time, in seconds, that the full operation lasted.

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

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

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

FILES

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

ENVIRONMENT

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

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

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

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

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

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

       NO_PROXY <comma-separated list of hosts/domains>
              list  of  host names that shouldn't go through any proxy. If set to an asterisk '*'
              only, it matches all hosts. Each name in this list is matched as  either  a  domain
              name which contains the hostname, or the hostname itself.

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

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

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:

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

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

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

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

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

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

EXIT CODES

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

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

       2      Failed to initialize.

       3      URL malformed. The syntax was not correct.

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

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

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

       7      Failed to connect to host.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       26     Read error. Various reading problems.

       27     Out of memory. A memory allocation request failed.

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

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

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

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

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

       35     SSL connect error. The SSL handshaking failed.

       36     Bad download resume. Couldn't continue an earlier aborted download.

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

       38     LDAP cannot bind. LDAP bind operation failed.

       39     LDAP search failed.

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

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

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

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

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

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

       49     Malformed telnet option.

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

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

       53     SSL crypto engine not found.

       54     Cannot set SSL crypto engine as default.

       55     Failed sending network data.

       56     Failure in receiving network data.

       58     Problem with the local certificate.

       59     Couldn't use specified SSL cipher.

       60     Peer certificate cannot be authenticated with known CA certificates.

       61     Unrecognized transfer encoding.

       62     Invalid LDAP URL.

       63     Maximum file size exceeded.

       64     Requested FTP SSL level failed.

       65     Sending the data requires a rewind that failed.

       66     Failed to initialise SSL Engine.

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

       68     File not found on TFTP server.

       69     Permission problem on TFTP server.

       70     Out of disk space on TFTP server.

       71     Illegal TFTP operation.

       72     Unknown TFTP transfer ID.

       73     File already exists (TFTP).

       74     No such user (TFTP).

       75     Character conversion failed.

       76     Character conversion functions required.

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

       78     The resource referenced in the URL does not exist.

       79     An unspecified error occurred during the SSH session.

       80     Failed to shut down the SSL connection.

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

       83     Issuer check failed (added in 7.19.0).

       84     The FTP PRET command failed

       85     RTSP: mismatch of CSeq numbers

       86     RTSP: mismatch of Session Identifiers

       87     unable to parse FTP file list

       88     FTP chunk callback reported error

       89     No connection available, the session will be queued

       90     SSL public key does not matched pinned public key

       91     Invalid SSL certificate status.

       92     Stream error in HTTP/2 framing layer.

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

AUTHORS / CONTRIBUTORS

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

WWW

       https://curl.haxx.se

SEE ALSO

       ftp(1), wget(1)