--abstract-unix-socket

(HTTP) Connect through an abstract Unix domain socket, instead of using the network. Note: netstat shows the path of anabstract 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 sup‐port. 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 theclient 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

(FTP SFTP) When used in an upload, this makes curl append to the target file instead of overwriting it. If the remote filedoesn'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 point‐less, unless you use it to override a previously set option that sets a different authentication method (such as --ntlm,

--digest,

Used together with -u, --user.See also --proxy-basic.

--cacert

(TLS) Tells curl to use the specified certificate file to verify the peer. The file may contain multiple CA certificates. Thecertificate(s) must be in PEM format. Normally curl is built to use a default file for this, so this option is typically usedto 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 certbundle. This option overrides that variable.The windows version of curl will automatically look for a CA certs file named ´curl-ca-bundle.crt´, either in the same direc‐tory as curl.exe, or in the Current Working Directory, or in any folder along your PATH.If curl is built against the NSS SSL library, the NSS PEM PKCS#11 module (libnsspem.so) needs to be available for this optionto work properly.(iOS and macOS only) If curl is built against Secure Transport, then this option is supported for backward compatibility withother SSL engines, but it should not be set. If the option is not set, then curl will use the certificates in the system anduser Keychain to verify the peer, which is the preferred method of verifying the peer's certificate chain.If this option is used several times, the last one will be used.

--capath

(TLS) Tells curl to use the specified certificate directory to verify the peer. Multiple paths can be provided by separatingthem with ":" (e.g. "path1:path2:path3"). The certificates must be in PEM format, and if curl is built against OpenSSL, thedirectory must have been processed using the c_rehash utility supplied with OpenSSL. Using --capath can allow OpenSSL-poweredcurl 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 servercertificate 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

(TLS) Tells curl what certificate type the provided certificate is in. PEM, DER and ENG are recognized types. If not speci‐fied, 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

(TLS) Tells curl to use the specified client certificate file when getting a file with HTTPS, FTPS or another SSL-based proto‐col. The certificate must be in PKCS#12 format if using Secure Transport, or PEM format if using any other engine. If theoptional password isn't specified, it will be queried for on the terminal. Note that this option assumes a "certificate" filethat 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 theNSS database defined by the environment variable SSL_DIR (or by default /etc/pki/nssdb). If the NSS PEM PKCS#11 module (lib‐nsspem.so) is available then PEM files may be loaded. If you want to use a file from the current directory, please precede itwith "./" 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 itis not recognized as an escape character.(iOS and macOS only) If curl is built against Secure Transport, then the certificate string can either be the name of a cer‐tificate/private key in the system or user keychain, or the path to a PKCS#12-encoded certificate and private key. If you wantto use a file from the current directory, please precede it with "./" prefix, in order to avoid confusion with a nickname.If this option is used several times, the last one will be used.See also --cert-type and --key and --key-type.

--ciphers

(TLS) Specifies which ciphers to use in the connection. The list of ciphers must specify valid ciphers. Read up on SSL cipherlist details on this URL:https://curl.haxx.se/docs/ssl-ciphers.htmlIf 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 thisoption is used and the server sends an unsupported encoding, curl will report an error.

-K

Specify a text file to read curl arguments from. The command line arguments found in the text file will be used as if theywere 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 equalssign. Long option names can optionally be given in the config file without the initial double dashes and if so, the colon orequals characters can be used as separators. If the option is specified with one or two dashes, there can be no colon orequals 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 followingescape sequences are available: \\, \", \t, \n, \r and \v. A backslash preceding any other letter is ignored. If the firstcolumn of a config line is a '#' character, the rest of the line will be treated as a comment. Only write one option per phys‐ical 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 simplywriting 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 defaultconfig 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, itthen 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.

-O

referer = "http://nowhereatall.example.com/"

--connect-timeout

Maximum time in seconds that you allow curl's connection to take. This only limits the connection phase, so if curl connectswithin 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

For a request to the given HOST1:PORT1 pair, connect to HOST2:PORT2 instead. This option is suitable to direct requests at aspecific server, e.g. at a specific cluster node in a cluster of servers. This option is only used to establish the networkconnection. It does NOT affect the hostname/port that is used for TLS/SSL (e.g. SNI, certificate verification) or for theapplication protocols. "HOST1" and "PORT1" may be the empty string, meaning "any host/port". "HOST2" and "PORT2" may also bethe 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 eithernumerical 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/Resume a previous file transfer at the given offset. The given offset is the exact number of bytes that will beskipped, 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 filesto figure that out.If this option is used several times, the last one will be used.See also -r, --range.

-c

(HTTP) Specify to which file you want curl to write all cookies after a completed operation. Curl writes all cookies from itsin-memory cookie storage to the given file at the end of operations. If no cookies are known, no data will be written. Thefile will be written using the Netscape cookie file format. If you set the file name to a single dash, "-", the cookies willbe written to stdout.This command line option will activate the cookie engine that makes curl record and use cookies. Another way to activate it isto 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

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

-b

(HTTP) Pass the data to the HTTP server in the Cookie header. It is supposedly the data previously received from the server ina "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. Thisoption also activates the cookie engine which will make curl record incoming cookies, which may be handy if you're using thisin combination with the -L, --location option or do multiple URL transfers on the same invoke.The file format of the file to read cookies from should be plain HTTP headers (Set-Cookie style) or the Netscape/Mozillacookie 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

--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 ifthe dirs it mentions already exist, no dir will be created.To create remote directories when using FTP or SFTP, try --ftp-create-dirs.

--crlf

(SMTP added in 7.40.0)

--crlfile

(TLS) Provide a file using PEM format with a Certificate Revocation List that may specify peer certificates that are to beconsidered revoked.If this option is used several times, the last one will be used.Added in 7.19.7.

--data-ascii

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

--data-binary

(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, --datadoes, except that newlines and carriage returns are preserved and conversions are never done.If this option is used several times, the ones following the first will append data as described in -d, --data.

--data-raw

(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

(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:contentThis 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!=contentThis will make curl URL-encode the content and pass that on. The preceding = symbol is not included in the data.name=contentThis will make curl URL-encode the content part and pass that on. Note that the name part is expected to be URL-encodedalready.@filenameThis will make curl load data from the given file (including any newlines), URL-encode that data and pass it on in thePOST.name@filenameThis will make curl load data from the given file (including any newlines), URL-encode that data and pass it on in thePOST. The name part gets an equal sign appended, resulting in name=urlencoded-file-content. Note that the name isexpected to be URL-encoded already.See also -d, --data and --data-raw. Added in 7.18.0.

-d

(HTTP) Sends the specified data in a POST request to the HTTP server, in the same way that a browser does when a user hasfilled 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.

--delegation

(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 pol‐icy.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 overthe 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 alwaysfirst attempt to use EPRT, then LPRT before using PORT, but with this option, it will use PORT right away. EPRT and LPRT areextensions to the original FTP protocol, and may not work on all servers, but they enable more functionality in a better waythan the traditional PORT command.

--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 orforce 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 firstattempt to use EPSV before PASV, but with this option, it will not try using EPSV.

--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

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

--dns-interface

(DNS) Tell curl to send outgoing DNS requests through <interface>. This option is a counterpart to --interface (which does notaffect 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

(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

(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

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

-D

(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 couldthen be read in a second curl invocation by using the -b, --cookie option! The -c, --cookie-jar option is a better way tostore 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

(TLS) Specify the path name to the Entropy Gathering Daemon socket. The socket is used to seed the random engine for SSL con‐nections.See also --random-file.

--engine

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

--expect100-timeout

(HTTP) Maximum time in seconds that you allow curl to wait for a 100-continue response when curl emits an Expects: 100-con‐tinue header in its request. By default curl will wait one second. This option accepts decimal values! When curl stops wait‐ing, 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. Bydefault, it will ignore errors if there are more URLs given and the last URL's success will determine the error code curlreturns. 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 thatare 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 combinethe two options, however note -f, --fail is not global and is therefore contained by -:, --next.Added in 7.52.0.

-f

(HTTP) Fail silently (no output at all) on server errors. This is mostly done to better enable scripts etc to better deal withfailed 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 whenauthentication 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 sendingapplication 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

(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'sany possibility that the string value may accidentally trigger the '@' or '<' features of -F, --form.See also -F, --form.

-F

(HTTP SMTP IMAP) For HTTP protocol family, this lets curl emulate a filled-in form in which a user has pressed the submit but‐ton. 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. Tojust 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 textfield from a file.Example: to send an image to an HTTP server, where 'profile' is the name of the form-field to which portrait.jpg will be theinput:curl -F profile=@portrait.jpg https://example.com/upload.cgiTo read content from stdin instead of a file, use - as the filename. This goes for both @ and < constructs. If stdin is notattached to a regular file, it is buffered first to determine its size and allow a possible resend. Defining a part's datafrom a named non-regular file (such as a named pipe or similar) is unfortunately not subject to buffering and will be effec‐tively read at transmission time; since the full size is unknown before the transfer starts, data is sent as chunks by HTTPand rejected by IMAP.You can also tell curl what Content-Type to use by using 'type=', in a manner similar to:curl -F "web=@index.html;type=text/html" example.comorcurl -F "name=daniel;type=text/foo" example.comYou can also explicitly change the name field of a file upload part by setting filename=, like this:curl -F "file=@localfile;filename=nameinpost" example.comIf filename/path contains ',' or ';', it must be quoted by double-quotes like:curl -F "file=@\"localfile\";filename=\"nameinpost\"" example.comorcurl -F 'file=@"localfile";filename="nameinpost"' example.comNote that if a filename/path is quoted by double-quotes, any double-quote or backslash within the filename must be escaped bybackslash.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.comYou can add custom headers to the field by setting headers=, likecurl -F "submit=OK;headers=\"X-submit-type: OK\"" example.comorcurl -F "submit=OK;headers=@headerfile" example.comThe headers= keyword may appear more that once and above notes about quoting apply. When headers are read from a file, Emptylines and lines starting with '#' are comments and ignored; each header can be folded by splitting between two words andstarting the continuation line with a space; embedded carriage-returns and trailing spaces are stripped. Here is an exampleof a header file contents:# This file contain two headers.

-header-1:

# The following header is folded.

-header-2:

another headerTo 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,

--ftp-account

(FTP) When an FTP server asks for "account data" after user name and password has been provided, this data is sent off usingthe ACCT command.If this option is used several times, the last one will be used.Added in 7.13.0.

--ftp-alternative-to-user

(FTP) If authenticating with the USER and PASS commands fails, send this command. When connecting to Tumbleweed's SecureTransport server over FTPS using a client certificate, using "SITE AUTH" will tell the server to retrieve the username fromthe 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 ofcurl is to fail. Using this option, curl will instead attempt to create missing directories.See also --create-dirs.

--ftp-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 fol‐lowing alternatives:multicwdcurl does a single CWD operation for each path part in the given URL. For deep hierarchies this means very many com‐mands. 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.singlecwdcurl 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 tooverride 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 mustthen 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) Reverses the default initiator/listener roles when connecting with FTP. This option makes curl use active mode. curlthen tells the server to connect back to the client's specified address and port, while passive mode asks the server to setupan IP address and port for it to connect to. <address> should be one of:interfacei.e "eth0" to specify which interface's IP address you want to use (Unix only)IP addressi.e "192.168.10.1" to specify the exact IP addresshost namei.e "my.host.domain" to specify the machine

--ftp-pret

(FTP) Tell curl to send a PRET command before PASV (and EPSV). Certain FTP servers, mainly drftpd, require this non-standardcommand 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 thedata 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

(FTP) Sets the CCC mode. The passive mode will not initiate the shutdown, but instead wait for the server to do it, and willnot reply to the shutdown from the server. The active mode initiates the shutdown and waits for a reply from the server.See also --ftp-ssl-ccc. Added in 7.16.2.

--ftp-ssl-ccc

(FTP) Use CCC (Clear Command Channel) Shuts down the SSL/TLS layer after authenticating. The rest of the control channel com‐munication will be unencrypted. This allows NAT routers to 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 transfersfor efficiency. Fails the transfer if the server doesn't support SSL/TLS.Added in 7.16.0.

-G

When used, this option will make all data specified with -d, --data, --data-binary or --data-urlencode to be used in an HTTPGET request instead of the POST request that otherwise would be used. The data will be appended to the URL with a '?' separa‐tor.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 youshould then instead enforce the alternative method you prefer.

-g

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 theyshould be encoded according to the URI standard.

-I

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

-H

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

-h

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

--hostpubmd5

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

-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 thatthe server supports HTTP/2 straight away. HTTPS requests will still do HTTP/2 the standard way with negotiated protocol ver‐sion in the TLS handshake.

--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 --http1.1and -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 willreport 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 the HTTP response headers in the output. The HTTP response headers can include things like server name, cookies, dateof the document, HTTP version and more...To view the request headers, consider the -v, --verbose option.See also -v, --verbose.

-k

(TLS) By default, every SSL connection curl makes is verified to be secure. This option allows curl to proceed and operateeven for server connections otherwise considered insecure.The server connection is verified by making sure the server's certificate contains the right name and verifies successfullyusing the cert store.See this online resource for further details:https://curl.haxx.se/docs/sslcerts.htmlSee also --proxy-insecure and --cacert.

--interface

Perform an operation using a specified interface. You can enter interface name, IP address or host name. An example could looklike: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 ran as root. More informa‐tion about Linux VRF: https://www.kernel.org/doc/Documentation/networking/vrf.txtSee also --dns-interface.

-4

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

This option tells curl to resolve names to IPv6 addresses only, and not for example try IPv4.See also --http1.1 and --http2. This option overrides -6, --ipv6.

-j

(HTTP) When curl is told to read cookies from a given file, this option will make it discard all "session cookies". This willbasically have the same effect as if a new session is started. Typical browsers always discard session cookies when they'reclosed down.See also -b, --cookie and -c, --cookie-jar.

--keepalive-time

This option sets the time a connection needs to remain idle before sending keepalive probes and the time between individualkeepalive 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

(TLS) Private key file type. Specify which type your --key provided private key is. DER, PEM, and ENG are supported. If notspecified, PEM is assumed.If this option is used several times, the last one will be used.

--key

(TLS SSH) Private key file name. Allows you to provide your private key in this separate file. For SSH, if not specified, curltries the following candidates in order:If this option is used several times, the last one will be used.

--krb

(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.

--libcurl

Append this option to any ordinary curl command line, and you will get a libcurl-using C source code written to the file thatdoes 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

Specify the maximum transfer rate you want curl to use - for both downloads and uploads. This feature is useful if you have alimited pipe and you'd like your transfer not to use your entire bandwidth. To make it slower than it otherwise would be.The given speed is measured in bytes/second, unless a suffix is appended. Appending 'k' or 'K' will count the number as kilo‐bytes, 'm' or 'M' makes it megabytes, while 'g' or 'G' makes it gigabytes. Examples: 200K, 3m and 1G.If you also use the -Y, --speed-limit option, that option will take precedence and might cripple the rate-limiting slightly,to help keeping the speed-limit logic working.If this option is used several times, the last one will be used.

-l

(FTP POP3) (FTP) When listing an FTP directory, this switch forces a name-only view. This is especially useful if the userwants 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 isparticularly 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 theemail's unique identifier rather than it's message id to make the request.Added in 7.21.5.

--local-port

Set a preferred single number or range (FROM-TO) of local port numbers to use for the connection(s). Note that port numbersby nature are a scarce resource that will be busy at times so setting this range to something too narrow might cause unneces‐sary 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 ormay not introduce a security breach if the site redirects you to a site to which you'll send your authentication info (whichis plaintext in the case of HTTP Basic authentication).See also -u, --user.

-L

(HTTP) If the server reports that the requested page has moved to a different location (indicated with a Location: header anda 3XX response code), this option will make curl redo the request on the new place. If used together with -i, --include or -I,

--login-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 onlyIMAP, POP3 and SMTP support login options. For more information about the login options please see RFC 2384, RFC 5092 and IETFdraft draft-earhart-url-smtp-00.txtIf this option is used several times, the last one will be used.Added in 7.34.0.

--mail-auth

(SMTP) Specify a single address. This will be used to specify the authentication address (identity) of a submitted messagethat is being relayed to another server.See also --mail-rcpt and --mail-from. Added in 7.25.0.

--mail-from

(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

(SMTP) Specify a single address, user name or mailing list name. Repeat this option several times to send to multiple recipi‐ents.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 anddomain (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. Display the huge help text.

--max-filesize

Specify the maximum size (in bytes) of a file to download. If the file requested is larger than this value, the transfer willnot 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 itmegabytes, 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 filetransfer ends up being larger than this given limit. This concerns both FTP and HTTP transfers.See also --limit-rate.

--max-redirs

(HTTP) Set maximum number of redirection-followings allowed. When -L, --location is used, is used to prevent curl from follow‐ing 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

Maximum time in seconds that you allow the whole operation to take. This is useful for preventing your batch jobs from hang‐ing for hours due to slow networks or links going down. Since 7.32.0, this option accepts decimal values, but the actualtimeout 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 inmemory and not stored in the local file system.Example to use a remote Metalink file:curl --metalink http://www.example.com/example.metalinkTo use a Metalink file in the local file system, use FILE protocol (file://):curl --metalink file://example.metalinkPlease note that if FILE protocol is disabled, there is no way to use a local Metalink file at the time of this writing. Alsonote that if --metalink and -i, --include are used together, --include will be ignored. This is because including headers inthe response will break Metalink parser and if the headers are included in the file described in Metalink file, hash checkwill fail.

--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/SSPIor SPNEGO.When using this option, you must also provide a fake -u, --user option to activate the authentication code properly. Sending a

-u

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

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

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

-:

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

--no-alpn

(HTTPS) Disable the ALPN TLS extension. ALPN is enabled by default if libcurl was built with an SSL library that supportsALPN. 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

Disables the buffering of the output stream. In normal work situations, curl will use a standard buffered output stream thatwill have the effect that it will output the data in chunks, not necessarily exactly when the data arrives. Using this optionwill 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 noth‐ing should ever get hurt by attempting to reuse SSL session-IDs, there seem to be broken SSL implementations in the wild thatmay 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

Comma-separated list of hosts which do not use a proxy, if one is specified. The only wildcard is a single * character, whichmatches all hosts, and effectively disables the proxy. Each name in this list is matched as either a domain which contains thehostname, or the hostname itself. For example, local.com would match local.com, local.com:80, and www.local.com, but notwww.notlocal.com.Since 7.53.0, This option overrides the environment variables that disable the proxy. If there's an environment variable dis‐abling a proxy, you can set noproxy list to "" to override it.Added in 7.19.4.

--ntlm-wb

(HTTP) Enables NTLM much in the style --ntlm does, but hand over the authentication to the separate binary ntlmauth applica‐tion that is executed when needed.See also --ntlm and --proxy-ntlm.

--negotiated

and --digest and --anyauth.

--oauth2-bearer

(IMAP POP3 SMTP) Specify the Bearer Token for OAUTH 2.0 server authentication. The Bearer Token is used in conjunction withthe 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

Write output to <file> instead of stdout. If you are using {} or [] to fetch multiple documents, you can use '#' followed by anumber 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 commandline, you can use it like this:curl -o aa example.com -o bb example.netand 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 theabove command line can also be written ascurl example.com example.net -o aa -o bbSee 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

(SSH TLS) Passphrase for the private keyIf 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 tostandards but with this option set you tell it not to do that.Added in 7.42.0.

--pinnedpubkey

(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 con‐tains a single public key in PEM or DER format, or any number of base64 encoded sha256 hashes preceded by ´sha256//´ and sepa‐rated by ´;´When negotiating a TLS or SSL connection, the server sends a certificate indicating its identity. A public key is extractedfrom this certificate and if it does not exactly match the public key provided to this option, curl will abort the connectionbefore sending or receiving any data.PEM/DER support:7.39.0: OpenSSL, GnuTLS and GSKit7.43.0: NSS and wolfSSL/CyaSSL7.47.0: mbedtls7.49.0: PolarSSL sha256 support:7.44.0: OpenSSL, GnuTLS, NSS and wolfSSL/CyaSSL.7.47.0: mbedtls7.49.0: 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, --loca‐tion.See also --post302 and --post303 and -L, --location. Added in 7.17.1.

--post302

(HTTP) Tells curl to respect RFC 7231/6.4.3 and not convert POST requests into GET requests when following a 302 redirection.The non-RFC behaviour is ubiquitous in web browsers, so curl does the conversion by default to maintain consistency. However,a server may require a POST to remain a POST after such a redirection. This option is meaningful only when using -L, --loca‐tion.See also --post301 and --post303 and -L, --location. Added in 7.19.1.

--post303

(HTTP) Tells curl to respect RFC 7231/6.4.4 and not convert POST requests into GET requests when following a 303 redirection.The non-RFC behaviour is ubiquitous in web browsers, so curl does the conversion by default to maintain consistency. However,a server may require a POST to remain a POST after such a redirection. This option is meaningful only when using -L, --loca‐tion.See also --post302 and --post301 and -L, --location. Added in 7.26.0.

--preproxy

Use the specified SOCKS proxy before connecting to an HTTP or HTTPS -x, --proxy. In such a case curl first connects to theSOCKS 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 curldefault 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 char‐acters 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.

-#

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 isknown. For transfers without a known size, it will instead output one '#' character for every 1024 bytes transferred.

--proto-default

Tells curl to use protocol for any URL missing a scheme name.Example:curl --proto-default https ftp.mozilla.orgAn 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

Tells curl to limit what protocols it may use on redirect. Protocols denied by --proto are not overridden by this option. See

--proto

Example, allow only HTTP and HTTPS on redirect:curl --proto-redir -all,http,https http://example.comBy default curl will allow all protocols on redirect except several disabled for security reasons: Since 7.19.4 FILE and SCPare disabled, and since 7.40.0 SMB and SMBS are also disabled. Specifying all or +all enables all protocols on redirect,including those disabled for security.Added in 7.20.2.

--proxy-anyauth

Tells curl to pick a suitable authentication method when communicating with the given HTTP proxy. This might cause an extrarequest/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 witha remote host. Basic is the default authentication method curl uses with proxies.See also -x, --proxy and --proxy-anyauth and --proxy-digest.

--proxy-cacert

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

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

Same as --cert-type but used in HTTPS proxy context.Added in 7.52.0.

--proxy-cert

Same as -E, --cert but used in HTTPS proxy context.Added in 7.52.0.

--proxy-ciphers

Same as --ciphers but used in HTTPS proxy context.Added in 7.52.0.

--proxy-crlfile

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 Digestwith a remote host.See also -x, --proxy and --proxy-anyauth and --proxy-basic.

--proxy-header

(HTTP) Extra header to include in the request when sending HTTP to a proxy. You may specify any number of extra headers. Thisis the equivalent option to -H, --header but is for proxy communication only like in CONNECT requests when you want a separateheader 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 thatas 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 inputfile. 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

Same as --key-type but used in HTTPS proxy context.Added in 7.52.0.

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

--proxy-pass

Same as --pass but used in HTTPS proxy context.Added in 7.52.0.

--proxy-service-name

This option allows you to change the service name for proxy negotiation.Added in 7.43.0.

--proxy-ssl-allow-beast

Same as --ssl-allow-beast but used in HTTPS proxy context.Added in 7.52.0.

--proxy-tlsauthtype

Same as --tlsauthtype but used in HTTPS proxy context.Added in 7.52.0.

--proxy-tlspassword

Same as --tlspassword but used in HTTPS proxy context.Added in 7.52.0.

--proxy-tlsuser

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

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 selectthe 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

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 wasadded 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 usehttp:// 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 aproxy, 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 protocolspecific operations might not be available. This is not the case if you can tunnel through the proxy, as one with the -p,

--proxytunnel

User and password that might be provided in the proxy string are URL decoded by curl. This allows you to pass in special char‐acters 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

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 willspecify an HTTP 1.0 protocol instead of the default HTTP 1.1.

-p

When an HTTP proxy is used -x, --proxy, this option will cause non-HTTP protocols to attempt to tunnel through the proxyinstead of merely using it to do HTTP-like operations. The tunnel approach is made with the HTTP proxy CONNECT request andrequires 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

(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 gen‐erally not required. Note that this public key extraction requires libcurl to be linked against a copy of libssh2 1.2.8 orhigher that is itself linked against OpenSSL.)

-Q

(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 transfercommand(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 cor‐rect 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 curlcontinue 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. Filenames may be quoted shell-style to embed spaces or special characters. Following is the list of all supported SFTP quote com‐mands:chgrp group fileThe chgrp command sets the group ID of the file named by the file operand to the group ID specified by the group oper‐and. The group operand is a decimal integer group ID.chmod mode fileThe chmod command modifies the file mode bits of the specified file. The mode operand is an octal integer mode number.chown user fileThe 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_fileThe ln and symlink commands create a symbolic link at the target_file location pointing to the source_file location.mkdir directory_nameThe 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 targetThe rename command renames the file or directory named by the source operand to the destination path named by the tar‐get operand.rm fileThe rm command removes the file specified by the file operand.rmdir directoryThe rmdir command removes the directory entry specified by the directory operand, provided it is empty.symlink source_file target_fileSee ln.

--random-file

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

-r

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

-499

500-999 specifies the second 500 bytes

-500

9500- specifies the bytes from offset 9500 and forward

-e

(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 URLwhen 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

(HTTP) This option tells the -O, --remote-name option to use the server-specified Content-Disposition filename instead ofextracting 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 beoverwritten 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 unex‐pected file names.WARNING: Exercise judicious use of this option, especially on Windows. A rogue server could send you the name of a DLL orother 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. Soif 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.

-R

When used, this will make curl attempt to figure out the timestamp of the remote file, and if that is available make the localfile 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 usefulwhen 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

(HTTP) Specifies a custom request method to use when communicating with the HTTP server. The specified request method will beused instead of the method otherwise used (which defaults to GET). Read the HTTP 1.1 specification for details and explana‐tions. Common additional HTTP requests include PUT and DELETE, but related technologies like WebDAV offers PROPFIND, COPY,MOVE and more.Normally you don't need this option. All sorts of GET, HEAD, POST and PUT requests are rather invoked by using dedicated com‐mand line options.This option only changes the actual word used in the HTTP request, it does not alter the way curl behaves. So for example ifyou 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 maycause 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

Provide a custom address for a specific host and port pair. Using this, you can make the curl requests(s) use a specifiedaddress and prevent the otherwise normally resolved address to be used. Consider it a sort of /etc/hosts alternative providedon the command line. The port number should be the number used for the specific protocol the host will be used for. It meansyou need several entries if you want to provide address for the same host but different ports.The provided address set by this option will be used even if -4, --ipv4 or -6, --ipv6 is set to make curl use another IP ver‐sion.Support for providing the IP address within [brackets] was added in 7.57.0.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 togetherwith --retry.Added in 7.52.0.

--retry-delay

Make curl sleep this amount of time before each retry when a transfer has failed with a transient error (it changes thedefault backoff time algorithm between retries). This option is only interesting if --retry is also used. Setting this delayto 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

The retry timer is reset before the first transfer attempt. Retries will be done as usual (see --retry) as long as the timerhasn't reached this given limit. Notice that if the timer hasn't reached the limit, the request will be made and while per‐forming, it may take longer than this given time period. To limit a single request´s maximum time, use -m, --max-time. Setthis 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

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 4xxresponse code or an HTTP 5xx response code.When curl is about to retry a transfer, it will first wait one second and then for all forthcoming retries it will double thewaiting time until it reaches 10 minutes which then will be the delay between the rest of the retries. By using --retry-delayyou 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

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

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

-s

Silent or quiet mode. Don't show progress meter or error messages. Makes Curl mute. It will still output the data you askfor, 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

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

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:// protocolprefix.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 isenabled 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 protec‐tion mode negotiation.Added in 7.19.4.

--socks5-gssapi-service

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

Use the specified SOCKS5 proxy (and let the proxy resolve the host name). If the port number is not specified, it is assumedat 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

Use the specified SOCKS5 proxy - but resolve the host name locally. If the port number is not specified, it is assumed at port1080.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 pre‐fix.Since 7.52.0, --preproxy can be used to specify a SOCKS proxy at the same time -x, --proxy is used with an HTTP/HTTPS proxy.In such a case curl first connects to the SOCKS proxy and then 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

If a download is slower than this given speed (in bytes per second) for speed-time seconds it gets aborted. speed-time is setwith -y, --speed-time and is 30 if not set.If this option is used several times, the last one will be used.

-y

If a download is slower than speed-limit bytes per second during a speed-time period, the download gets aborted. If speed-timeis 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 optionisn't used, the SSL layer may use workarounds known to cause interoperability problems with some older SSL implementations.WARNING: this option loosens the SSL security, and by using this flag you ask for exactly that.Added in 7.25.0.

--ssl-no-revoke

(WinSSL) This option tells curl to disable certificate revocation checks. WARNING: this option loosens the SSL security, andby 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.

-2

(SSL) Forces curl to use SSL version 2 when negotiating with a remote SSL server. Sometimes curl is built without SSLv2 sup‐port. SSLv2 is widely considered insecure (see RFC 6176).See also --http1.1 and --http2. -2, --sslv2 requires that the underlying libcurl was built to support TLS. This option over‐rides -3, --sslv3 and -1, --tlsv1 and --tlsv1.1 and --tlsv1.2.

-3

(SSL) Forces curl to use SSL version 3 when negotiating with a remote SSL server. Sometimes curl is built without SSLv3 sup‐port. SSLv3 is widely considered insecure (see RFC 7568).See also --http1.1 and --http2. -3, --sslv3 requires that the underlying libcurl was built to support TLS. This option over‐rides -2, --sslv2 and -1, --tlsv1 and --tlsv1.1 and --tlsv1.2.

--stderr

Redirect all writes to stderr to the specified file instead. If the file name is a plain '-', it is instead written to stdout.If this option is used several times, the last one will be used.See also -v, --verbose and -s, --silent.

--suppress-connect-headers

When -p, --proxytunnel is used and a CONNECT request is made don't output proxy CONNECT response headers. This option is meantto be used with -D, --dump-header or -i, --include which are used to show protocol headers in the output. It has no effect ondebug 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

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

(TFTP) Set TFTP BLKSIZE option (must be >512). This is the block size that curl will try to use when transferring data to orfrom 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 thisoption is used --tftp-blksize is ignored.Added in 7.48.0.

-z

(HTTP FTP) Request a file that has been modified later than the given time and date, or one that has been modified before thattime. The <date expression> can be all sorts of date strings or if it doesn't match any internal ones, it is taken as a file‐name and tries to get the modification date (mtime) from <file> instead. See the curl_getdate(3) man pages for date expressiondetails.Start the date expression with a dash (-) to make it request for a document that is older than the given date/time, default isa document that is newer than the specified date/time.If this option is used several times, the last one will be used.

--tls-max

(SSL) VERSION defines maximum supported TLS version. A minimum is defined by arguments tlsv1.0 or tlsv1.1 or tlsv1.2.defaultUse up to recommended TLS version.1.0 Use up to TLSv1.0.1.1 Use up to TLSv1.1.1.2 Use up to TLSv1.2.1.3 Use up to TLSv1.3.See also --tlsv1.0 and --tlsv1.1 and --tlsv1.2. --tls-max requires that the underlying libcurl was built to support TLS. Added in7.54.0.

--tlsauthtype

Set TLS authentication type. Currently, the only supported option is "SRP", for TLS-SRP (RFC 5054). If --tlsuser and

--tlspassword

Added in 7.21.4.

--tlsuser

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 when connecting to a remote TLS server.Added in 7.34.0.

--tlsv1.1

(TLS) Forces curl to use TLS version 1.1 when connecting to a remote TLS server.Added in 7.34.0.

--tlsv1.2

(TLS) Forces curl to use TLS version 1.2 when connecting to a remote TLS server.Added in 7.34.0.

--tlsv1.3

(TLS) Forces curl to use TLS version 1.3 when connecting to a remote TLS server.Note that TLS 1.3 is only supported by a subset of TLS backends. At the time of this writing, they are BoringSSL, NSS, andSecure Transport (on iOS 11 or later, and macOS 10.13 or later).Added in 7.52.0.

-1

(SSL) Tells curl to use TLS version 1.x when negotiating with a remote TLS server. That means TLS version 1.0, 1.1 or 1.2.See also --http1.1 and --http2. -1, --tlsv1 requires that the underlying libcurl was built to support TLS. This option over‐rides --tlsv1.1 and --tlsv1.2 and --tlsv1.3.

--tr-encoding

(HTTP) Request a compressed Transfer-Encoding response using one of the algorithms curl supports, and uncompress the datawhile receiving it.Added in 7.21.6.

--trace-ascii

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

-"

This is very similar to --trace, but leaves out the hex part and only shows the ASCII part of the dump. It makes smaller out‐put 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

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

--unix-socket

(HTTP) Connect through this Unix domain socket, instead of using the network.Added in 7.40.0.

-T

This transfers the specified local file to the remote URL. If there is no file part in the specified URL, curl will append thelocal file name. NOTE that you must use a trailing / on the last directory to really prove to Curl that there is no file nameor curl will think that your last directory name is the remote file name to use. That will most likely cause the upload opera‐tion 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 beinguploaded.You can specify one -T, --upload-file for each URL on the command line. Each -T, --upload-file + URL pair specifies what toupload and to where. curl also supports "globbing" of the -T, --upload-file argument, meaning that you can upload multiplefiles 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.comor evencurl -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 setof headers and mail body formatted correctly by the user as curl will not transcode nor encode it further in any way.

--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 HTTPwill 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

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

-A

(HTTP) Specify the User-Agent string to send to the HTTP server. To encode blanks in the string, surround the string with sin‐gle quote marks. This can also be set with the -H, --header option of course.If this option is used several times, the last one will be used.

-V

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-develop‐ers only!AsynchDNSThis curl uses asynchronous name resolves. Asynchronous name resolves can be done using either the c-ares or thethreaded resolver backends.SPNEGO SPNEGO authentication is supported.LargefileThis curl supports transfers of large files, files larger than 2GB.IDN This curl supports IDN - international domain names.GSS-APIGSS-API is supported.SSPI SSPI is supported.TLS-SRPSRP (Secure Remote Password) authentication is supported for TLS.HTTP2 HTTP/2 support has been built-in.UnixSocketsUnix sockets support is provided.HTTPS-proxyThis curl is built to support HTTPS proxy.MetalinkThis curl supports Metalink (both version 3 and 4 (RFC 5854)), which describes mirrors and hashes. curl will use mir‐rors 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".

-w

Make curl display information on stdout after a completed transfer. The format is a string that may contain plain text mixedwith any number of variables. The format can be specified as a literal "string", or you can have curl read the format from afile 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 newlineby using \n, a carriage return with \r and a tab space with \t.NOTE: The %-symbol is a special symbol in the win32-environment, where all occurrences of % must be doubled when using thisoption.The variables available are:content_type The Content-Type of the requested document, if there was any.filename_effectiveThe ultimate filename that curl writes out to. This is only meaningful if curl is told to write to a file withthe -O, --remote-name or -o, --output option. It's most useful in combination with the -J, --remote-header-nameoption. (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 thealias 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 in7.12.4)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 in7.29.0)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_resultThe result of the HTTPS proxy's SSL peer certificate verification that was requested. 0 means the verificationwas 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), thisvariable 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_resultThe result of the SSL peer certificate verification that was requested. 0 means the verification was success‐ful. (Added in 7.19.0)time_appconnectThe time, in seconds, it took from the start until the SSL/SSH/etc connect/handshake to the remote host wascompleted. (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_namelookupThe time, in seconds, it took from the start until the name resolving was completed.time_pretransferThe time, in seconds, it took from the start until the file transfer was just about to begin. This includes allpre-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 trans‐fer before the final transaction was started. time_redirect shows the complete execution time for multipleredirections. (Added in 7.12.3)time_starttransferThe time, in seconds, it took from the start until the first byte was just about to be transferred. Thisincludes 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 thefile system does not support extended attributes, a warning is issued.FILES~/.curlrcDefault config file, see -K, --config for details.ENVIRONMENTThe environment variables can be specified in lower case or upper case. The lower case version has precedence. http_proxy is anexception 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 aURL. FTP, FTPS, POP3, IMAP, SMTP, LDAP etc.ALL_PROXY [protocol://]<host>[:port]Sets the proxy server to use if no protocol-specific proxy is set.NO_PROXY <comma-separated list of hosts>list of host names that shouldn't go through any proxy. If set to a asterisk '*' only, it matches all hosts.Since 7.53.0, this environment variable disable the proxy even if specify -x, --proxy option. That is NO_PROXY=direct.exam‐ple.com curl -x http://proxy.example.com http://direct.example.com accesses the target URL directly, and NO_PROXY=direct.exam‐ple.com curl -x http://proxy.example.com http://somewhere.example.com accesses the target URL through proxy.PROXY PROTOCOL PREFIXESSince 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 HTTPproxy.The supported proxy protocol prefixes are as follows:http://Makes it use it as a HTTP proxy. The default if no scheme prefix is used.https://Makes it treated as a HTTPS proxy.socks4://Makes it the equivalent of --socks4socks4a://Makes it the equivalent of --socks4asocks5://Makes it the equivalent of --socks5socks5h://Makes it the equivalent of --socks5-hostnameEXIT CODESThere are a bunch of different error codes and their corresponding error messages that may appear during bad conditions. At the timeof 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. Mostoften 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 sentover 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 prob‐lems, 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 orabove. 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 PASVinstead!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 andrejected. 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 failed85 RTSP: mismatch of CSeq numbers86 RTSP: mismatch of Session Identifiers87 unable to parse FTP file list88 FTP chunk callback reported error89 No connection available, the session will be queued90 SSL public key does not matched pinned public key91 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 / CONTRIBUTORSDaniel Stenberg is the main author, but the whole list of contributors is found in the separate THANKS file.WWWhttps://curl.haxx.se