curl

(HTTP) Connect through an abstract Unix domain socket, instead of using the network. Note: netstat shows the path of an abstract socket prefixed with "@", however the <path> argument should not have this leading character. If --abstract-unix-socket is provided several times, the last set value is used. Example: curl --abstract-unix-socket socketpath https://example.com See also --unix-socket.

(HTTPS) Enable the alt-svc parser. If the filename points to an existing alt-svc cache file, that gets used. After a completed transfer, the cache is saved to the filename again if it has been modified. Specify a "" filename (zero length) to avoid loading/saving and make curl just handle the cache in memory. If this option is used several times, curl loads contents from all the files but the last one is used for saving. --alt-svc can be used several times in a command line Example: curl --alt-svc svc.txt https://example.com Added in 7.64.1. See also --resolve and --connect-to.

(HTTP) Figure out authentication method automatically, and use the most secure one the remote site claims to support. This is done by first doing a request and checking the response-headers, thus possibly inducing an extra network round-trip. This option is used instead of setting a specific authentication method, which you can do with --basic, --digest, --ntlm, and --negotiate. Using --anyauth is not recommended if you do uploads from stdin, since it may require data to be sent twice and then the client must be able to rewind. If the need should arise when uploading from stdin, the upload ope

(FTP SFTP) When used in an upload, this option makes curl append to the target file instead of overwriting it. If the remote file does not exist, it is created. Note that this flag is ignored by some SFTP servers (including OpenSSH). Providing --append multiple times has no extra effect. Disable it again with --no-append. Example: curl --upload-file local --append ftp://example.com/ See also -r, --range and -C, --continue-at.

(HTTP) Use AWS V4 signature authentication in the transfer. The provider argument is a string that is used by the algorithm when creating outgoing authentication headers. The region argument is a string that points to a geographic area of a resources collection (region-code) when the region name is omitted from the endpoint. The service argument is a string that points to a function provided by a cloud (service-code) when the service name is omitted from the endpoint. If --aws-sigv4 is provided several times, the last set value is used. Example: curl --aws-sigv4 "aws:amz:us-east-2:es" --user "

(HTTP) Use HTTP Basic authentication with the remote host. This method is the default and this option is usually pointless, unless you use it to override a previously set option that sets a different authentication method (such as --ntlm, --digest, or --negotiate). Used together with -u, --user. Providing --basic multiple times has no extra effect. Example: curl -u name:password --basic https://example.com See also --proxy-basic.

(TLS) Use the operating system's native CA store for certificate verification. This option is independent of other CA certificate locations set at run time or build time. Those locations are searched in addition to the native CA store. This option works with OpenSSL and its forks (LibreSSL, BoringSSL, etc) on Windows. (Added in 7.71.0) This option works with wolfSSL on Windows, Linux (Debian, Ubuntu, Gentoo, Fedora, RHEL), macOS, Android and iOS. (Added in 8.3.0) This option works with GnuTLS. (Added in 8.5.0) This option works with rustls on Windows, macOS, Android and iOS. On Linux it is equ

(TLS) Use the specified certificate file to verify the peer. The file may contain multiple CA certificates. The certificate(s) must be in PEM format. Normally curl is built to use a default file for this, so this option is typically used to alter that default file. curl recognizes the environment variable named 'CURL_CA_BUNDLE' if it is set and the TLS backend is not Schannel, and uses the given path as a path to a CA cert bundle. This option overrides that variable. (Windows) curl automatically looks for a CA certs file named 'curl-ca-bundle.crt', either in the same directory as curl.exe, or

(TLS) Use the specified certificate directory to verify the peer. Multiple paths can be provided by separating them with colon (":") (e.g. "path1:path2:path3"). The certificates must be in PEM format, and if curl is built against OpenSSL, the directory must have been processed using the c_rehash utility supplied with OpenSSL. Using --capath can allow OpenSSL-powered curl to make SSL-connections much more efficiently than using --cacert if the --cacert file contains many CA certificates. If this option is set, the default capath value is ignored. If --capath is provided several times, the last

(TLS) Use the specified client certificate file when getting a file with HTTPS, FTPS or another SSL-based protocol. The certificate must be in PKCS#12 format if using Secure Transport, or PEM format if using any other engine. If the optional password is not specified, it is queried for on the terminal. Note that this option assumes a certificate file that is the private key and the client certificate concatenated. See -E, --cert and --key to specify them independently. In the <certificate> portion of the argument, you must escape the character ":" as "\:" so that it is not recognized as the pa

(TLS) Verify the status of the server certificate by using the Certificate Status Request (aka. OCSP stapling) TLS extension. If this option is enabled and the server sends an invalid (e.g. expired) response, if the response suggests that the server certificate has been revoked, or no response at all is received, the verification fails. This support is currently only implemented in the OpenSSL and GnuTLS backends. Providing --cert-status multiple times has no extra effect. Disable it again with --no-cert-status. Example: curl --cert-status https://example.com See also --pinnedpubkey.

(TLS) Set type of the provided client certificate. PEM, DER, ENG, PROV and P12 are recognized types. The default type depends on the TLS backend and is usually PEM, however for Secure Transport and Schannel it is P12. If -E, --cert is a pkcs11: URI then ENG or PROV is the default type (depending on OpenSSL version). If --cert-type is provided several times, the last set value is used. Example: curl --cert-type PEM --cert file https://example.com See also -E, --cert, --key and --key-type.

(TLS) Specify which cipher suites to use in the connection if it negotiates TLS 1.2 (1.1, 1.0). The list of ciphers suites must specify valid ciphers. Read up on cipher suite details on this URL: https://curl.se/docs/ssl-ciphers.html If --ciphers is provided several times, the last set value is used. Example: curl --ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256 https://example.com See also --tls13-ciphers, --proxy-ciphers and --curves.

(HTTP) Request a compressed response using one of the algorithms curl supports, and automatically decompress the content. Response headers are not modified when saved, so if they are "interpreted" separately again at a later point they might appear to be saying that the content is (still) compressed; while in fact it has already been decompressed. If this option is used and the server sends an unsupported encoding, curl reports an error. This is a request, not an order; the server may or may not deliver data compressed. Providing --compressed multiple times has no extra effect. Disable it agai

(SCP SFTP) Enable SSH compression. This is a request, not an order; the server may or may not do it. Providing --compressed-ssh multiple times has no extra effect. Disable it again with --no-compressed-ssh. Example: curl --compressed-ssh sftp://example.com/ See also --compressed.

Specify a text file to read curl arguments from. The command line arguments found in the text file are used as if they were provided on the command line. Options and their parameters must be specified on the same line in the file, separated by whitespace, colon, or the equals sign. Long option names can optionally be given in the config file without the initial double dashes and if so, the colon or equals characters can be used as separators. If the option is specified with one or two dashes, there can be no colon or equals character between the option and its parameter. If the parameter conta

Maximum time in seconds that you allow curl's connection to take. This only limits the connection phase, so if curl connects within the given period it continues - if not it exits. This option accepts decimal values. The decimal value needs to be provided using a dot (.) as decimal separator - not the local version even if it might be using another separator. The connection phase is considered complete when the DNS lookup and requested TCP, TLS or QUIC handshakes are done. If --connect-timeout is provided several times, the last set value is used. Examples: curl --connect-timeout 20 https://ex

For a request intended for the "HOST1:PORT1" pair, connect to "HOST2:PORT2" instead. This option is only used to establish the network connection. It does NOT affect the hostname/port number that is used for TLS/SSL (e.g. SNI, certificate verification) or for the application protocols. "HOST1" and "PORT1" may be empty strings, meaning any host or any port number. "HOST2" and "PORT2" may also be empty strings, meaning use the request's original hostname and port number. A hostname specified to this option is compared as a string, so it needs to match the name used in the request URL. It can be

Resume a previous transfer from the given byte offset. The given offset is the exact number of bytes that are skipped, counting from the beginning of the source file before it is transferred to the destination. If used with uploads, the FTP server command SIZE is not used by curl. Use "-C -" to instruct curl to automatically find out where/how to resume the transfer. It then uses the given output/input files to figure that out. When using this option for HTTP uploads using POST or PUT, functionality is not guaranteed. The HTTP protocol has no standard interoperable resume upload and curl uses

(HTTP) This option has two slightly separate cookie sending functions. Either: pass the exact data to send to the HTTP server in the Cookie header. It is supposedly data previously received from the server in a "Set-Cookie:" line. The data should be in the format "NAME1=VALUE1; NAME2=VALUE2". When given a set of specific cookies, curl populates its cookie header with this content explicitly in all outgoing request(s). If multiple requests are done due to authentication, followed redirects or similar, they all get this cookie header passed on. Or: If no "=" symbol is used in the argument, it is

(HTTP) Specify to which file you want curl to write all cookies after a completed operation. curl writes all cookies from its in-memory cookie storage to the given file at the end of operations. Even if no cookies are known, a file is created so that it removes any formerly existing cookies from the file. The file uses the Netscape cookie file format. If you set the filename to a single minus, "-", the cookies are written to stdout. The file specified with -c, --cookie-jar is only used for output. No cookies are read from the file. To read cookies, use the -b, --cookie option. Both options can

When used in conjunction with the -o, --output option, curl creates the necessary local directory hierarchy as needed. This option creates the directories mentioned with the -o, --output option combined with the path possibly set with --output-dir. If the combined output filename uses no directory, or if the directories it mentions already exist, no directories are created. Created directories are made with mode 0750 on Unix-style file systems. To create remote directories when using FTP or SFTP, try --ftp-create-dirs. Providing --create-dirs multiple times has no extra effect. Disable it agai

(SFTP SCP FILE) When curl is used to create files remotely using one of the supported protocols, this option allows the user to set which 'mode' to set on the file at creation time, instead of the default 0644. This option takes an octal number as argument. If --create-file-mode is provided several times, the last set value is used. Example: curl --create-file-mode 0777 -T localfile sftp://example.com/new Added in 7.75.0. See also --ftp-create-dirs.

(FTP SMTP) Convert line feeds to carriage return plus line feeds in upload. Useful for MVS (OS/390). Providing --crlf multiple times has no extra effect. Disable it again with --no-crlf. Example: curl --crlf -T file ftp://example.com/ See also -B, --use-ascii.

(TLS) Provide a file using PEM format with a Certificate Revocation List that may specify peer certificates that are to be considered revoked. If --crlfile is provided several times, the last set value is used. Example: curl --crlfile rejects.txt https://example.com See also --cacert and --capath.

(TLS) Set specific curves to use during SSL session establishment according to RFC 8422, 5.1. Multiple algorithms can be provided by separating them with ":" (e.g. "X25519:P-521"). The parameter is available identically in the OpenSSL "s_client" and "s_server" utilities. --curves allows a OpenSSL powered curl to make SSL-connections with exactly the (EC) curve requested by the client, avoiding nontransparent client/server negotiations. If this option is set, the default curves list built into OpenSSL are ignored. If --curves is provided several times, the last set value is used. Example: curl

(HTTP MQTT) Send the specified data in a POST request to the HTTP server, in the same way that a browser does when a user has filled in an HTML form and presses the submit button. This option makes curl pass the data to the server using the content-type application/x-www-form-urlencoded. Compared to -F, --form. --data-raw is almost the same but does not have a special interpretation of the @ character. To post data purely binary, you should instead use the --data-binary option. To URL-encode the value of a form field you may use --data-urlencode. If any of these options is used more than once

(HTTP) This option is just an alias for -d, --data. --data-ascii can be used several times in a command line Example: curl --data-ascii @file https://example.com See also --data-binary, --data-raw and --data-urlencode.

(HTTP) Post data exactly as specified with no extra processing whatsoever. If you start the data with the letter @, the rest should be a filename. "@-" makes curl read the data from stdin. Data is posted in a similar manner as -d, --data does, except that newlines and carriage returns are preserved and conversions are never done. Like -d, --data the default content-type sent to the server is application/x-www-form-urlencoded. If you want the data to be treated as arbitrary binary data by the server then set the content-type to octet-stream: -H "Content-Type: application/octet-stream". If this

(HTTP) Post data similarly to -d, --data but without the special interpretation of the @ character. --data-raw can be used several times in a command line Examples: curl --data-raw "hello" https://example.com curl --data-raw "@at@at@" https://example.com See also -d, --data.

(HTTP) Post 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:

(GSS/kerberos) Set LEVEL what curl is allowed to delegate when it comes to user credentials.

(HTTP) Enable HTTP Digest authentication. This authentication scheme avoids sending the password over the wire in clear text. Use this in combination with the normal -u, --user option to set username and password. Providing --digest multiple times has no extra effect. Disable it again with --no-digest. Example: curl -u name:password --digest https://example.com This option is mutually exclusive with --basic, --ntlm and --negotiate. See also -u, --user, --proxy-digest and --anyauth.

If used as the first parameter on the command line, the curlrc config file is not read or used. See the -K, --config for details on the default config file search path. Providing --disable multiple times has no extra effect. Disable it again with --no-disable. Example: curl -q https://example.com See also -K, --config.

(FTP) Disable the use of the EPRT and LPRT commands when doing active FTP transfers. curl normally first attempts to use EPRT before using PORT, but with this option, it uses PORT right away. EPRT is an extension to the original FTP protocol, and does not work on all servers, but enables more functionality in a better way than the traditional PORT command. --eprt can be used to explicitly enable EPRT again and --no-eprt is an alias for --disable-eprt. If the server is accessed using IPv6, this option has no effect as EPRT is necessary then. Disabling EPRT only changes the active behavior. If y

(FTP) Disable the use of the EPSV command when doing passive FTP transfers. curl normally first attempts to use EPSV before PASV, but with this option, it does not try EPSV. --epsv can be used to explicitly enable EPSV again and --no-epsv is an alias for --disable-epsv. If the server is an IPv6 host, this option has 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. Providing --disable-epsv multiple times has no extra effect. Disable it again with --no-disable-epsv. Example: curl --disable-

Exit with error if passed a URL containing a username. Probably most useful when the URL is being provided at runtime or similar. Providing --disallow-username-in-url multiple times has no extra effect. Disable it again with --no-disallow-username-in-url. Example: curl --disallow-username-in-url https://example.com Added in 7.61.0. See also --proto.

(DNS) Send outgoing DNS requests through the given interface. This option is a counterpart to --interface (which does not affect DNS). The supplied string must be an interface name (not an address). If --dns-interface is provided several times, the last set value is used. Example: curl --dns-interface eth0 https://example.com --dns-interface requires that libcurl is built to support c-ares. See also --dns-ipv4-addr and --dns-ipv6-addr.

(DNS) Bind to a specific IP address when making IPv4 DNS requests, so that the DNS requests originate from this address. The argument should be a single IPv4 address. If --dns-ipv4-addr is provided several times, the last set value is used. Example: curl --dns-ipv4-addr 10.1.2.3 https://example.com --dns-ipv4-addr requires that libcurl is built to support c-ares. See also --dns-interface and --dns-ipv6-addr.

(DNS) Bind to a specific IP address when making IPv6 DNS requests, so that the DNS requests originate from this address. The argument should be a single IPv6 address. If --dns-ipv6-addr is provided several times, the last set value is used. Example: curl --dns-ipv6-addr 2a04:4e42::561 https://example.com --dns-ipv6-addr requires that libcurl is built to support c-ares. See also --dns-interface and --dns-ipv4-addr.

(DNS) Set the list of DNS servers to be used instead of the system default. The list of IP addresses should be separated with commas. Port numbers may also optionally be given, appended to the IP address separated with a colon. If --dns-servers is provided several times, the last set value is used. Examples: curl --dns-servers 192.168.0.1,192.168.0.2 https://example.com curl --dns-servers 10.0.0.1:53 https://example.com --dns-servers requires that libcurl is built to support c-ares. See also --dns-interface and --dns-ipv4-addr.

Same as --cert-status but used for DoH (DNS-over-HTTPS). Verify the status of the DoH servers' certificate by using the Certificate Status Request (aka. OCSP stapling) TLS extension. If this option is enabled and the DoH server sends an invalid (e.g. expired) response, if the response suggests that the server certificate has been revoked, or no response at all is received, the verification fails. This support is currently only implemented in the OpenSSL and GnuTLS backends. Providing --doh-cert-status multiple times has no extra effect. Disable it again with --no-doh-cert-status. Example: curl

By default, every connection curl makes to a DoH server is verified to be secure before the transfer takes place. This option tells curl to skip the verification step and proceed without checking. WARNING: using this option makes the DoH transfer and name resolution insecure. This option is equivalent to -k, --insecure and --proxy-insecure but used for DoH (DNS-over-HTTPS) only. Providing --doh-insecure multiple times has no extra effect. Disable it again with --no-doh-insecure. Example: curl --doh-insecure --doh-url https://doh.example https://example.com Added in 7.76.0. See also --doh-url,

Specify which DNS-over-HTTPS (DoH) server to use to resolve hostnames, instead of using the default name resolver mechanism. The URL must be HTTPS. Some SSL options that you set for your transfer also apply to DoH since the name lookups take place over SSL. However, the certificate verification settings are not inherited but are controlled separately via --doh-insecure and --doh-cert-status. By default, DoH is bypassed when initially looking up DNS records of the DoH server. You can specify the IP address(es) of the DoH server with --resolve to avoid this. This option is unset if an empty stri

(TLS) Write the CA bundle embedded in curl to standard output, then quit. If curl was not built with a default CA bundle embedded, the output is empty. Providing --dump-ca-embed multiple times has no extra effect. Disable it again with --no-dump-ca-embed. Example: curl --dump-ca-embed Added in 8.10.0. See also --ca-native, --cacert, --capath, --proxy-ca-native, --proxy-cacert and --proxy-capath.

(HTTP FTP) Write the received protocol headers to the specified file. If no headers are received, the use of this option creates an empty file. Specify "-" as filename (a single minus) to have it written to stdout. Starting in curl 8.10.0, specify "%" (a single percent sign) as filename writes the output to stderr. When used in FTP, the FTP server response lines are considered being "headers" and thus are saved there. Starting in curl 8.11.0, using the --create-dirs option can also create missing directory components for the path provided in -D, --dump-header. Having multiple transfers in one

(HTTPS) Specify how to do ECH (Encrypted Client Hello). The values allowed for <config> can be:

(TLS) Deprecated option (added in 7.84.0). Prior to that it only had an effect on curl if built to use old versions of OpenSSL. Specify the path name to the Entropy Gathering Daemon socket. The socket is used to seed the random engine for SSL connections. If --egd-file is provided several times, the last set value is used. Example: curl --egd-file /random/here https://example.com See also --random-file.

(TLS) Select the OpenSSL crypto engine to use for cipher operations. Use --engine list to print a list of build-time supported engines. Note that not all (and possibly none) of the engines may be available at runtime. If --engine is provided several times, the last set value is used. Example: curl --engine flavor https://example.com See also --ciphers and --curves.

(HTTP) Make a conditional HTTP request for the specific ETag read from the given file by sending a custom If-None-Match header using the stored ETag. For correct results, make sure that the specified file contains only a single line with the desired ETag. A non-existing or empty file is treated as an empty ETag. Use the option --etag-save to first save the ETag from a response, and then use this option to compare against the saved ETag in a subsequent request. Use this option with a single URL only. If --etag-compare is provided several times, the last set value is used. Example: curl --etag-c

(HTTP) Save an HTTP ETag to the specified file. An ETag is a caching related header, usually returned in a response. Use this option with a single URL only. If no ETag is sent by the server, an empty file is created. In many situations you want to use an existing etag in the request to avoid downloading the same resource again but also save the new etag if it has indeed changed, by using both etag options --etag-save and --etag-compare with the same filename, in the same command line. Starting in curl 8.12.0, using the --create-dirs option can also create missing directory components for the p

(HTTP) Maximum time in seconds that you allow curl to wait for a 100-continue response when curl emits an Expects: 100-continue header in its request. By default curl waits one second. This option accepts decimal values. When curl stops waiting, it continues as if a response was received. The decimal value needs to be provided using a dot (".") as decimal separator - not the local version even if it might be using another separator. If --expect100-timeout is provided several times, the last set value is used. Example: curl --expect100-timeout 2.5 -T file https://example.com See also --connect-

(HTTP) Fail with error code 22 and with no response body output at all for HTTP transfers returning HTTP response codes at 400 or greater. In normal cases when an HTTP server fails to deliver a document, it returns a body of text stating so (which often also describes why and more) and a 4xx HTTP response code. This command line option prevents curl from outputting that data and instead returns error 22 early. By default, curl does not consider HTTP response codes to indicate failure. To get both the error code and also save the content, use --fail-with-body instead. This method is not fail-sa

Fail and exit on the first detected transfer error. When curl is used to do multiple transfers on the command line, it attempts to operate on each given URL, one by one. By default, it ignores errors if there are more URLs given and the last URL's success determines the error code curl returns. Early failures are "hidden" by subsequent successful transfers. Using this option, curl instead returns an error on the first transfer that fails, independent of the amount of URLs that are given on the command line. This way, no transfer failures go undetected by scripts and similar. This option does n

(HTTP) Return an error on server errors where the HTTP response code is 400 or greater). 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 option allows curl to output and save that content but also to return error 22. This is an alternative option to -f, --fail which makes curl fail for the same circumstances but without saving the content. Providing --fail-with-body multiple times has no extra effect. Disable it again with --no-fail-with-body. Example: curl --fail-with-body https://example.c

(TLS) Use false start during the TLS handshake. False start is a mode where a TLS client starts sending application data before verifying the server's Finished message, thus saving a round trip when performing a full handshake. This functionality is currently only implemented in the Secure Transport (on iOS 7.0 or later, or macOS 10.9 or later) backend. Providing --false-start multiple times has no extra effect. Disable it again with --no-false-start. Example: curl --false-start https://example.com See also --tcp-fastopen.

(HTTP SMTP IMAP) For the HTTP protocol family, emulate a filled-in form in which a user has pressed the submit button. This makes curl POST data using the Content-Type multipart/form-data according to RFC 2388. For SMTP and IMAP protocols, this composes a multipart mail message to transmit. This enables uploading of binary files etc. To force the 'content' part to be a file, prefix the filename with an @ sign. To just get the content part from a file, prefix the filename with the symbol <. The difference between @ and < is then that @ makes a file get attached in the post as a file upload, whi

(HTTP imap smtp) Pass on names of multipart form fields and files using backslash-escaping instead of percent-encoding. If --form-escape is provided several times, the last set value is used. Example: curl --form-escape -F 'field\name=curl' -F 'file=@load"this' https://example.com Added in 7.81.0. See also -F, --form.

(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 is any possibility that the string value may accidentally trigger the @ or < features of -F, --form. --form-string can be used several times in a command line Example: curl --form-string "name=data" https://example.com See also -F, --form.

(FTP) When an FTP server asks for "account data" after username and password has been provided, this data is sent off using the ACCT command. If --ftp-account is provided several times, the last set value is used. Example: curl --ftp-account "mr.robot" ftp://example.com/ See also -u, --user.

(FTP) If authenticating with the USER and PASS commands fails, send this command. When connecting to Tumbleweed's Secure Transport server over FTPS using a client certificate, using "SITE AUTH" tells the server to retrieve the username from the certificate. If --ftp-alternative-to-user is provided several times, the last set value is used. Example: curl --ftp-alternative-to-user "U53r" ftp://example.com See also --ftp-account and -u, --user.

(FTP SFTP) When an FTP or SFTP URL/operation uses a path that does not currently exist on the server, the standard behavior of curl is to fail. Using this option, curl instead attempts to create missing directories. Providing --ftp-create-dirs multiple times has no extra effect. Disable it again with --no-ftp-create-dirs. Example: curl --ftp-create-dirs -T file ftp://example.com/remote/path/file See also --create-dirs.

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

(FTP) Use passive mode for the data connection. Passive is the internal default behavior, but using this option can be used to override a previous -P, --ftp-port option. Reversing an enforced passive really is not doable but you must then instead enforce the correct -P, --ftp-port again. Passive mode means that curl tries the EPSV command first and then PASV, unless --disable-epsv is used. Providing --ftp-pasv multiple times has no extra effect. Example: curl --ftp-pasv ftp://example.com/ This option is mutually exclusive with -P, --ftp-port. See also --disable-epsv.

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

(FTP) Send a PRET command before PASV (and EPSV). Certain FTP servers, mainly drftpd, require this non-standard command for directory listings as well as up and downloads in PASV mode. Providing --ftp-pret multiple times has no extra effect. Disable it again with --no-ftp-pret. Example: curl --ftp-pret ftp://example.com/ See also -P, --ftp-port and --ftp-pasv.

(FTP) Do not use the IP address the server suggests in its response to curl's PASV command when curl connects the data connection. Instead curl reuses the same IP address it already uses for the control connection. This option is enabled by default (added in 7.74.0). This option has no effect if PORT, EPRT or EPSV is used instead of PASV. Providing --ftp-skip-pasv-ip multiple times has no extra effect. Disable it again with --no-ftp-skip-pasv-ip. Example: curl --ftp-skip-pasv-ip ftp://example.com/ See also --ftp-pasv.

(FTP) Use CCC (Clear Command Channel) Shuts down the SSL/TLS layer after authenticating. The rest of the control channel communication is unencrypted. This allows NAT routers to follow the FTP transaction. The default mode is passive. Providing --ftp-ssl-ccc multiple times has no extra effect. Disable it again with --no-ftp-ssl-ccc. Example: curl --ftp-ssl-ccc ftps://example.com/ See also --ssl and --ftp-ssl-ccc-mode.

(FTP) Set the CCC mode. The passive mode does not initiate the shutdown, but instead waits for the server to do it, and does not reply to the shutdown from the server. The active mode initiates the shutdown and waits for a reply from the server. Providing --ftp-ssl-ccc-mode multiple times has no extra effect. Disable it again with --no-ftp-ssl-ccc-mode. Example: curl --ftp-ssl-ccc-mode active --ftp-ssl-ccc ftps://example.com/ See also --ftp-ssl-ccc.

(FTP) Require SSL/TLS for the FTP login, clear for transfer. Allows secure authentication, but non-encrypted data transfers for efficiency. Fails the transfer if the server does not support SSL/TLS. Providing --ftp-ssl-control multiple times has no extra effect. Disable it again with --no-ftp-ssl-control. Example: curl --ftp-ssl-control ftp://example.com See also --ssl.

(HTTP) When used, this option makes all data specified with -d, --data, --data-binary or --data-urlencode to be used in an HTTP GET request instead of the POST request that otherwise would be used. curl appends the provided data to the URL as a query string. If used in combination with -I, --head, the POST data is instead appended to the URL with a HEAD request. Providing --get multiple times has no extra effect. Disable it again with --no-get. Examples: curl --get https://example.com curl --get -d "tool=curl" -d "age=old" https://example.com curl --get -I -d "tool=curl" https://example.com Se

Switch off the URL globbing function. When you set this option, you can specify URLs that contain the letters {}[] without having curl itself interpret them. Note that these letters are not normal legal URL contents but they should be encoded according to the URI standard. Providing --globoff multiple times has no extra effect. Disable it again with --no-globoff. Example: curl -g "https://example.com/{[]}}}}" See also -K, --config and -q, --disable.

Set the timeout for Happy Eyeballs. Happy Eyeballs is an algorithm that attempts to connect to both IPv4 and IPv6 addresses for dual-stack hosts, giving IPv6 a head-start of the specified number of milliseconds. If the IPv6 address cannot be connected to within that time, then a connection attempt is made to the IPv4 address in parallel. The first connection to be established is the one that is used. The range of suggested useful values is limited. Happy Eyeballs RFC 6555 says "It is RECOMMENDED that connection attempts be paced 150-250 ms apart to balance human factors against network load."

(HTTP) Set a client IP in HAProxy PROXY protocol v1 header at the beginning of the connection. For valid requests, IPv4 addresses must be indicated as a series of exactly 4 integers in the range [0..255] inclusive written in decimal representation separated by exactly one dot between each other. Heading zeroes are not permitted in front of numbers in order to avoid any possible confusion with octal numbers. IPv6 addresses must be indicated as series of 4 hexadecimal digits (upper or lower case) delimited by colons between each other, with the acceptance of one double colon sequence to replace

(HTTP) Send a HAProxy PROXY protocol v1 header at the beginning of the connection. This is used by some load balancers and reverse proxies to indicate the client's true IP address and port. This option is primarily useful when sending test requests to a service that expects this header. Providing --haproxy-protocol multiple times has no extra effect. Disable it again with --no-haproxy-protocol. Example: curl --haproxy-protocol https://example.com Added in 7.60.0. See also -x, --proxy.

(HTTP FTP FILE) Fetch the headers only. HTTP-servers feature the command HEAD which this uses to get nothing but the header of a document. When used on an FTP or FILE URL, curl displays the file size and last modification time only. Providing --head multiple times has no extra effect. Disable it again with --no-head. Example: curl -I https://example.com See also -G, --get, -v, --verbose and --trace-ascii.

(HTTP IMAP SMTP) Extra header to include in information sent. When used within an HTTP request, it is added to the regular request headers. For an IMAP or SMTP MIME uploaded mail built with -F, --form options, it is prepended to the resulting MIME document, effectively including it at the mail global level. It does not affect raw uploaded mails. You may specify any number of extra headers. Note that if you should add a custom header that has the same name as one of the internal ones curl would use, your externally set header is used instead of the internal one. This allows you to make even tri

Usage help. Provide help for the subject given as an optional argument. If no argument is provided, curl displays the most important command line arguments. The argument can either be a category or a command line option. When a category is provided, curl shows all command line options within the given category. Specify category "all" to list all available options. If "category" is specified, curl displays all available help categories. If the provided subject is instead an existing command line option, specified either in its short form with a single dash and a single letter, or in the long fo

(SFTP SCP) Pass a string containing 32 hexadecimal digits. The string should be the 128 bit MD5 checksum of the remote host's public key, curl refuses the connection with the host unless the checksums match. If --hostpubmd5 is provided several times, the last set value is used. Example: curl --hostpubmd5 e5c1c49020640a5ab0f2034854c321a8 sftp://example.com/ See also --hostpubsha256.

(SFTP SCP) Pass a string containing a Base64-encoded SHA256 hash of the remote host's public key. curl refuses the connection with the host unless the hashes match. This feature requires libcurl to be built with libssh2 and does not work with other SSH backends. If --hostpubsha256 is provided several times, the last set value is used. Example: curl --hostpubsha256 NDVkMTQxMGQ1ODdmMjQ3MjczYjAyOTY5MmRkMjVmNDQ= sftp://example.com/ Added in 7.80.0. See also --hostpubmd5.

(HTTPS) Enable HSTS for the transfer. If the filename points to an existing HSTS cache file, that is used. After a completed transfer, the cache is saved to the filename again if it has been modified. If curl is told to use HTTP:// for a transfer involving a hostname that exists in the HSTS cache, it upgrades the transfer to use HTTPS. Each HSTS cache entry has an individual lifetime after which the upgrade is no longer performed. Specify a "" filename (zero length) to avoid loading/saving and make curl just handle HSTS in memory. If this option is used several times, curl loads contents from

(HTTP) Accept an HTTP version 0.9 response. HTTP/0.9 is a response without headers and therefore you can also connect with this to non-HTTP servers and still get a response since curl simply transparently downgrades - if allowed. HTTP/0.9 is disabled by default (added in 7.66.0) Providing --http0.9 multiple times has no extra effect. Disable it again with --no-http0.9. Example: curl --http0.9 https://example.com Added in 7.64.0. See also --http1.1, --http2 and --http3.

(HTTP) Use HTTP version 1.0 instead of using its internally preferred HTTP version. Providing --http1.0 multiple times has no extra effect. Example: curl --http1.0 https://example.com This option is mutually exclusive with --http1.1, --http2, --http2-prior-knowledge and --http3. See also --http0.9 and --http1.1.

(HTTP) Use HTTP version 1.1. This is the default with HTTP:// URLs. Providing --http1.1 multiple times has no extra effect. Example: curl --http1.1 https://example.com This option is mutually exclusive with --http1.0, --http2, --http2-prior-knowledge and --http3. See also --http1.0 and --http0.9.

(HTTP) Use HTTP/2. For HTTPS, this means curl negotiates HTTP/2 in the TLS handshake. curl does this by default. For HTTP, this means curl attempts to upgrade the request to HTTP/2 using the Upgrade: request header. When curl uses HTTP/2 over HTTPS, it does not itself insist on TLS 1.2 or higher even though that is required by the specification. A user can add this version requirement with --tlsv1.2. Providing --http2 multiple times has no extra effect. Example: curl --http2 https://example.com --http2 requires that libcurl is built to support HTTP/2. This option is mutually exclusive with --h

(HTTP) Issue a non-TLS HTTP request using HTTP/2 directly without HTTP/1.1 Upgrade. It requires prior knowledge that the server supports HTTP/2 straight away. HTTPS requests still do HTTP/2 the standard way with negotiated protocol versions in the TLS handshake. Since 8.10.0 if this option is set for an HTTPS request then the application layer protocol version (ALPN) offered to the server is only HTTP/2. Prior to that both HTTP/1.1 and HTTP/2 were offered. Providing --http2-prior-knowledge multiple times has no extra effect. Disable it again with --no-http2-prior-knowledge. Example: curl --htt

(HTTP) Attempt HTTP/3 to the host in the URL, but fallback to earlier HTTP versions if the HTTP/3 connection establishment fails or is slow. HTTP/3 is only available for HTTPS and not for HTTP URLs. This option allows a user to avoid using the Alt-Svc method of upgrading to HTTP/3 when you know or suspect that the target speaks HTTP/3 on the given host and port. When asked to use HTTP/3, curl issues a separate attempt to use older HTTP versions with a slight delay, so if the HTTP/3 transfer fails or is slow, curl still tries to proceed with an older HTTP version. The fallback performs the regu

(HTTP) Instruct curl to use HTTP/3 to the host in the URL, with no fallback to earlier HTTP versions. HTTP/3 can only be used for HTTPS and not for HTTP URLs. For HTTP, this option triggers an error. This option allows a user to avoid using the Alt-Svc method of upgrading to HTTP/3 when you know that the target speaks HTTP/3 on the given host and port. This option makes curl fail if a QUIC connection cannot be established, it does not attempt any other HTTP versions on its own. Use --http3 for similar functionality with a fallback. Providing --http3-only multiple times has no extra effect. Exa

(FTP HTTP) For HTTP, ignore the Content-Length header. This is particularly useful for servers running Apache 1.x, which reports incorrect Content-Length for files larger than 2 gigabytes. For FTP, this makes curl skip the SIZE command to figure out the size before downloading a file. Providing --ignore-content-length multiple times has no extra effect. Disable it again with --no-ignore-content-length. Example: curl --ignore-content-length https://example.com See also --ftp-skip-pasv-ip.

(TLS SFTP SCP) By default, every secure connection curl makes is verified to be secure before the transfer takes place. This option makes curl skip the verification step and proceed without checking. When this option is not used for protocols using TLS, curl verifies the server's TLS certificate before it continues: that the certificate contains the right name which matches the hostname used in the URL and that the certificate has been signed by a CA certificate present in the cert store. See this online resource for further details: https://curl.se/docs/sslcerts.html For SFTP and SCP, this op

Perform the operation using a specified interface. You can enter interface name, IP address or hostname. If you prefer to be specific, you can use the following special syntax:

(All) Set Type of Service (TOS) for IPv4 or Traffic Class for IPv6. The values allowed for <string> can be a numeric value between 1 and 255 or one of the following: CS0, CS1, CS2, CS3, CS4, CS5, CS6, CS7, AF11, AF12, AF13, AF21, AF22, AF23, AF31, AF32, AF33, AF41, AF42, AF43, EF, VOICE-ADMIT, ECT1, ECT0, CE, LE, LOWCOST, LOWDELAY, THROUGHPUT, RELIABILITY, MINCOST If --ip-tos is provided several times, the last set value is used. Example: curl --ip-tos CS5 https://example.com Added in 8.9.0. See also --tcp-nodelay and --vlan-priority.

(IPFS) Specify which gateway to use for IPFS and IPNS URLs. Not specifying this instead makes curl check if the IPFS_GATEWAY environment variable is set, or if a "~/.ipfs/gateway" file holding the gateway URL exists. If you run a local IPFS node, this gateway is by default available under "http://localhost:8080". A full example URL would look like: curl --ipfs-gateway http://localhost:8080 \ ipfs://bafybeigagd5nmnn2iys2f3 There are many public IPFS gateways. See for example: https://ipfs.github.io/public-gateway-checker/ If you opt to go for a remote gateway you need to be aware that you compl

Use IPv4 addresses only when resolving hostnames, and not for example try IPv6. Providing --ipv4 multiple times has no extra effect. Example: curl --ipv4 https://example.com This option is mutually exclusive with -6, --ipv6. See also --http1.1 and --http2.

Use IPv6 addresses only when resolving hostnames, and not for example try IPv4. Your resolver may respond to an IPv6-only resolve request by returning IPv6 addresses that contain "mapped" IPv4 addresses for compatibility purposes. macOS is known to do this. Providing --ipv6 multiple times has no extra effect. Example: curl --ipv6 https://example.com This option is mutually exclusive with -4, --ipv4. See also --http1.1 and --http2.

(HTTP) Send the specified JSON data in a POST request to the HTTP server. --json works as a shortcut for passing on these three options: --data-binary [arg] --header "Content-Type: application/json" --header "Accept: application/json" There is no verification that the passed in data is actual JSON or that the syntax is correct. If you start the data with the letter @, the rest should be a filename to read the data from, or a single dash (-) if you want curl to read the data from stdin. Posting data from a file named 'foobar' would thus be done with --json @foobar and to instead read the data f

(HTTP) When curl is told to read cookies from a given file, this option makes it discard all "session cookies". This has the same effect as if a new session is started. Typical browsers discard session cookies when they are closed down. Providing --junk-session-cookies multiple times has no extra effect. Disable it again with --no-junk-session-cookies. Example: curl --junk-session-cookies -b cookies.txt https://example.com See also -b, --cookie and -c, --cookie-jar.

Set the maximum number of keepalive probes TCP should send but get no response before dropping the connection. This option is usually used in conjunction with --keepalive-time. This option is supported on Linux, *BSD/macOS, Windows >=10.0.16299, Solaris 11.4, and recent AIX, HP-UX and more. This option has no effect if --no-keepalive is used. If unspecified, the option defaults to 9. If --keepalive-cnt is provided several times, the last set value is used. Example: curl --keepalive-cnt 3 https://example.com Added in 8.9.0. See also --keepalive-time and --no-keepalive.

Set the time a connection needs to remain idle before sending keepalive probes and the time between individual keepalive probes. It is currently effective on operating systems offering the "TCP_KEEPIDLE" and "TCP_KEEPINTVL" socket options (meaning Linux, *BSD/macOS, Windows, Solaris, and recent AIX, HP-UX and more). Keepalive is used by the TCP stack to detect broken networks on idle connections. The number of missed keepalive probes before declaring the connection down is OS dependent and is commonly 8 (*BSD/macOS/AIX), 9 (Linux/AIX) or 5/10 (Windows), and this number can be changed by specif

(TLS SSH) Private key filename. Allows you to provide your private key in this separate file. For SSH, if not specified, curl tries the following candidates in order: "~/.ssh/id_rsa", "~/.ssh/id_dsa", "./id_rsa", "./id_dsa". If curl is built against OpenSSL library, and the engine pkcs11 or pkcs11 provider is available, then a PKCS#11 URI (RFC 7512) can be used to specify a private key located in a PKCS#11 device. A string beginning with "pkcs11:" is interpreted as a PKCS#11 URI. If a PKCS#11 URI is provided, then the --engine option is set as "pkcs11" if none was provided and the --key-type o

(TLS) Private key file type. Specify which type your --key provided private key is. DER, PEM, and ENG are supported. If not specified, PEM is assumed. If --key-type is provided several times, the last set value is used. Example: curl --key-type DER --key here https://example.com See also --key.

(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' is used. If --krb is provided several times, the last set value is used. Example: curl --krb clear ftp://example.com/ --krb requires that libcurl is built to support Kerberos. See also --delegation and --ssl.

Append this option to any ordinary curl command line, and you get libcurl-using C source code written to the file that does the equivalent of what your command-line operation does. This option is global and does not need to be specified for each use of --next. If --libcurl is provided several times, the last set value is used. Example: curl --libcurl client.c https://example.com See also -v, --verbose.

Specify the maximum transfer rate you want curl to use - for both downloads and uploads. This feature is useful if you have a limited pipe and you would 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' counts the number as kilobytes, 'm' or 'M' makes it megabytes, while 'g' or 'G' makes it gigabytes. The suffixes (k, M, G, T, P) are 1024 based. For example 1k is 1024. Examples: 200K, 3m and 1G. The rate limiting logic works on averaging the transfer s

(FTP POP3 SFTP FILE) When listing an FTP directory, force a name-only view. Maybe particularly useful if the user wants to machine-parse the contents of an FTP directory since the normal directory view does not use a standard look or format. When used like this, the option causes an 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. When listing an SFTP directory, this switch forces a name-only view, one per line. This is especially useful if the user wants to machine-p

Set a preferred single number or range (FROM-TO) of local port numbers to use for the connection(s). Note that port numbers by nature are a scarce resource so setting this range to something too narrow might cause unnecessary connection setup failures. If --local-port is provided several times, the last set value is used. Example: curl --local-port 1000-3000 https://example.com See also -g, --globoff.

(HTTP) If the server reports that the requested page has moved to a different location (indicated with a Location: header and a 3XX response code), this option makes curl redo the request to the new place. If used together with -i, --show-headers or -I, --head, headers from all requested pages are shown. When authentication is used, or when sending a cookie with "-H Cookie:", curl only sends its credentials to the initial host. If a redirect takes curl to a different host, it does not get the credentials passed on. See --location-trusted on how to change this. Limit the amount of redirects to

(HTTP) Instruct curl to follow HTTP redirects like -L, --location, but permit curl to send credentials and other secrets along to other hosts than the initial one. This may or may not introduce a security breach if the site redirects you to a site to which you send this sensitive data to. Another host means that one or more of hostname, protocol scheme or port number changed. This option also allows curl to pass long cookies set explicitly with -H, --header. Providing --location-trusted multiple times has no extra effect. Disable it again with --no-location-trusted. Examples: curl --location-t

(IMAP LDAP POP3 SMTP) Specify the login options to use during server authentication. You can use login options to specify protocol specific options that may be used during authentication. At present only IMAP, POP3 and SMTP support login options. For more information about login options please see RFC 2384, RFC 5092 and the IETF draft https://datatracker.ietf.org/doc/html/draft-earhart-url-smtp-00 Since 8.2.0, IMAP supports the login option "AUTH=+LOGIN". With this option, curl uses the plain (not SASL) "LOGIN IMAP" command even if the server advertises SASL authentication. Care should be take

(SMTP) Specify a single address. This is used to specify the authentication address (identity) of a submitted message that is being relayed to another server. If --mail-auth is provided several times, the last set value is used. Example: curl --mail-auth user@example.com -T mail smtp://example.com/ See also --mail-rcpt and --mail-from.

(SMTP) Specify a single address that the given mail should get sent from. If --mail-from is provided several times, the last set value is used. Example: curl --mail-from user@example.com -T mail smtp://example.com/ See also --mail-rcpt and --mail-auth.

(SMTP) Specify a single email address, username or mailing list name. Repeat this option several times to send to multiple recipients. When performing an address verification (VRFY command), the recipient should be specified as the username or username and domain (as per Section 3.5 of RFC 5321). When performing a mailing list expand (EXPN command), the recipient should be specified using the mailing list name, such as "Friends" or "London-Office". --mail-rcpt can be used several times in a command line Example: curl --mail-rcpt user@example.net smtp://example.com See also --mail-rcpt-allowfai

(SMTP) When sending data to multiple recipients, by default curl aborts SMTP conversation if at least one of the recipients causes RCPT TO command to return an error. The default behavior can be changed by passing --mail-rcpt-allowfails command-line option which makes curl ignore errors and proceed with the remaining valid recipients. If all recipients trigger RCPT TO failures and this flag is specified, curl still aborts the SMTP conversation and returns the error received from to the last RCPT TO command. Providing --mail-rcpt-allowfails multiple times has no extra effect. Disable it again w

Manual. Display the huge help text. Example: curl --manual See also -v, --verbose, --libcurl and --trace.

(FTP HTTP MQTT) When set to a non-zero value, it specifies the maximum size (in bytes) of a file to download. If the file requested is larger than this value, the transfer does not start and curl returns with exit code 63. Setting the maximum value to zero disables the limit. A size modifier may be used. For example, Appending 'k' or 'K' counts the number as kilobytes, 'm' or 'M' makes it megabytes, while 'g' or 'G' makes it gigabytes. Examples: 200K, 3m and 1G. NOTE: before curl 8.4.0, when the file size is not known prior to download, for such files this option has no effect even if the file

(HTTP) Set the maximum number of redirections to follow. When -L, --location is used, to prevent curl from following too many redirects, by default, the limit is set to 50 redirects. Set this option to -1 to make it unlimited. If --max-redirs is provided several times, the last set value is used. Example: curl --max-redirs 3 --location https://example.com See also -L, --location.

Set the maximum time in seconds that you allow each transfer to take. Prevents your batch jobs from hanging for hours due to slow networks or links going down. This option accepts decimal values. If you enable retrying the transfer (--retry) then the maximum time counter is reset each time the transfer is retried. You can use --retry-max-time to limit the retry time. The decimal value needs to be provided using a dot (.) as decimal separator - not the local version even if it might be using another separator. If --max-time is provided several times, the last set value is used. Examples: curl -

This option was previously used to specify a Metalink resource. Metalink support is disabled in curl for security reasons (added in 7.78.0). If --metalink is provided several times, the last set value is used. Example: curl --metalink file https://example.com See also -Z, --parallel.

Enable the use of Multipath TCP (MPTCP) for connections. MPTCP is an extension to the standard TCP that allows multiple TCP streams over different network paths between the same source and destination. This can enhance bandwidth and improve reliability by using multiple paths simultaneously. MPTCP is beneficial in networks where multiple paths exist between clients and servers, such as mobile networks where a device may switch between WiFi and cellular data or in wired networks with multiple Internet Service Providers. This option is currently only supported on Linux starting from kernel 5.6.

(HTTP) Enable Negotiate (SPNEGO) authentication. This option requires a library built with GSS-API or SSPI support. Use -V, --version to see if your curl supports GSS-API/SSPI or SPNEGO. When using this option, you must also provide a fake -u, --user option to activate the authentication code properly. Sending a '-u :' is enough as the username and password from the -u, --user option are not actually used. Providing --negotiate multiple times has no extra effect. Example: curl --negotiate -u : https://example.com See also --basic, --ntlm, --anyauth and --proxy-negotiate.

Make curl scan the .netrc file in the user's home directory for login name and password. This is typically used for FTP on Unix. If used with HTTP, curl enables user authentication. See netrc(5) and ftp(1) for details on the file format. curl does not complain if that file does not have the right permissions (it should be neither world- nor group-readable). The environment variable "HOME" is used to find the home directory. On Windows two filenames in the home directory are checked: .netrc and _netrc, preferring the former. Older versions on Windows checked for _netrc only. A quick and simple

Set the netrc file to use. Similar to -n, --netrc, except that you also provide the path (absolute or relative). It abides by --netrc-optional if specified. If --netrc-file is provided several times, the last set value is used. Example: curl --netrc-file netrc https://example.com This option is mutually exclusive with -n, --netrc. See also -n, --netrc, -u, --user and -K, --config.

Similar to -n, --netrc, but this option makes the .netrc usage optional and not mandatory as the -n, --netrc option does. Providing --netrc-optional multiple times has no extra effect. Disable it again with --no-netrc-optional. Example: curl --netrc-optional https://example.com This option is mutually exclusive with -n, --netrc. See also --netrc-file.

Use a separate operation for the following URL and associated options. This allows you to send several URL requests, each with their own specific options, for example, such as different usernames or custom requests for each. -:, --next resets all local options and only global ones have their values survive over to the operation following the -:, --next instruction. Global options include -v, --verbose, --trace, --trace-ascii and --fail-early. For example, you can do both a GET and a POST in a single command line: curl www1.example.com --next -d postthis www2.example.com --next can be used seve

(HTTPS) Disable the ALPN TLS extension. ALPN is enabled by default if libcurl was built with an SSL library that supports ALPN. ALPN is used by a libcurl that supports HTTP/2 to negotiate HTTP/2 support with the server during https sessions. Note that this is the negated option name documented. You can use --alpn to enable ALPN. Providing --no-alpn multiple times has no extra effect. Disable it again with --alpn. Example: curl --no-alpn https://example.com --no-alpn requires that libcurl is built to support TLS. See also --no-npn and --http2.

Disable the buffering of the output stream. In normal work situations, curl uses a standard buffered output stream that has the effect that it outputs the data in chunks, not necessarily exactly when the data arrives. Using this option disables that buffering. Note that this is the negated option name documented. You can use --buffer to enable buffering again. Providing --no-buffer multiple times has no extra effect. Disable it again with --buffer. Example: curl --no-buffer https://example.com See also -#, --progress-bar.

When used in conjunction with the -o, --output, -J, --remote-header-name, -O, --remote-name, or --remote-name-all options, curl avoids overwriting files that already exist. Instead, a dot and a number gets appended to the name of the file that would be created, up to filename.100 after which it does not create any file. Note that this is the negated option name documented. You can thus use --clobber to enforce the clobbering, even if -J, --remote-header-name is specified. The -C, --continue-at option cannot be used together with --no-clobber. Providing --no-clobber multiple times has no extra

Disable 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. Providing --no-keepalive multiple times has no extra effect. Disable it again with --keepalive. Example: curl --no-keepalive https://example.com See also --keepalive-time and --keepalive-cnt.

(HTTPS) curl never uses NPN, this option has no effect (added in 7.86.0). 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. Providing --no-npn multiple times has no extra effect. Disable it again with --npn. Example: curl --no-npn https://example.com --no-npn requires that libcurl is built to support TLS. See also --no-alpn and --http2.

Option to switch off the progress meter output without muting or otherwise affecting warning and informational messages like -s, --silent does. Note that this is the negated option name documented. You can thus use --progress-meter to enable the progress meter again. Providing --no-progress-meter multiple times has no extra effect. Disable it again with --progress-meter. Example: curl --no-progress-meter -o store https://example.com Added in 7.67.0. See also -v, --verbose and -s, --silent.

(TLS) Disable curl's use of SSL session-ID caching. By default all transfers are done using the cache. Note that while nothing should ever get hurt by attempting to reuse SSL session-IDs, there seem to be broken SSL implementations in the wild that may require you to disable this in order for you to succeed. Note that this is the negated option name documented. You can thus use --sessionid to enforce session-ID caching. Providing --no-sessionid multiple times has no extra effect. Disable it again with --sessionid. Example: curl --no-sessionid https://example.com See also -k, --insecure.

Comma-separated list of hosts for which not to use a proxy, if one is specified. The only wildcard is a single "*" character, which matches all hosts, and effectively disables the proxy. Each name in this list is matched as either a domain which contains the hostname, or the hostname itself. For example, "local.com" would match "local.com", "local.com:80", and "www.local.com", but not "www.notlocal.com". This option overrides the environment variables that disable the proxy ("no_proxy" and "NO_PROXY"). If there is an environment variable disabling a proxy, you can set the no proxy list to "" t

(HTTP) Use NTLM authentication. The NTLM authentication method was designed by Microsoft and is used by IIS web servers. It is a proprietary protocol, reverse-engineered by clever people and implemented in curl based on their efforts. This kind of behavior should not be endorsed, you should encourage everyone who uses NTLM to switch to a public and documented authentication method instead, such as Digest. If you want to enable NTLM for your proxy authentication, then use --proxy-ntlm. Providing --ntlm multiple times has no extra effect. Example: curl --ntlm -u user:password https://example.com

(HTTP) Deprecated option (added in 8.8.0). Enabled NTLM much in the style --ntlm does, but handed over the authentication to a separate executable that was executed when needed. Providing --ntlm-wb multiple times has no extra effect. Example: curl --ntlm-wb -u user:password https://example.com See also --ntlm and --proxy-ntlm.

(IMAP LDAP POP3 SMTP HTTP) Specify the Bearer Token for OAUTH 2.0 server authentication. The Bearer Token is used in conjunction with the username which can be specified as part of the --url or -u, --user options. The Bearer Token and username are formatted according to RFC 6750. If --oauth2-bearer is provided several times, the last set value is used. Example: curl --oauth2-bearer "mF_9.B5f-4.1JqM" https://example.com See also --basic, --ntlm and --digest.

Write output to the given file instead of stdout. If you are using globbing to fetch multiple documents, you should quote the URL and you can use "#" followed by a number in the filename. That variable is then 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].example" -o "#1_#2" You may use this option as many times as the number of URLs you have. For example, if you specify two URLs on the same command line, you can use it like this: curl -o aa example.com

Specify the directory in which files should be stored, when -O, --remote-name or -o, --output are used. The given output directory is used for all URLs and output options on the command line, up until the first -:, --next. If the specified target directory does not exist, the operation fails unless --create-dirs is also used. If --output-dir is provided several times, the last set value is used. Example: curl --output-dir "tmp" -O https://example.com Added in 7.73.0. See also -O, --remote-name and -J, --remote-header-name.

Make curl perform all transfers in parallel as compared to the regular serial manner. Parallel transfer means that curl runs up to N concurrent transfers simultaneously and if there are more than N transfers to handle, it starts new ones when earlier transfers finish. With parallel transfers, the progress meter output is different from when doing serial transfers, as it then displays the transfer status for multiple transfers in a single line. The maximum amount of concurrent transfers is set with --parallel-max and it defaults to 50. This option is global and does not need to be specified for

When doing parallel transfers, this option instructs curl to prefer opening up more connections in parallel at once rather than waiting to see if new transfers can be added as multiplexed streams on another connection. By default, without this option set, curl prefers to wait a little and multiplex new transfers over existing connections. It keeps the number of connections low at the expense of risking a slightly slower transfer startup. This option is global and does not need to be specified for each use of --next. Providing --parallel-immediate multiple times has no extra effect. Disable it

When asked to do parallel transfers, using -Z, --parallel, this option controls the maximum amount of transfers to do simultaneously. The default is 50. 300 is the largest supported value. This option is global and does not need to be specified for each use of --next. If --parallel-max is provided several times, the last set value is used. Example: curl --parallel-max 100 -Z https://example.com ftp://example.com/ Added in 7.66.0. See also -Z, --parallel.

(SSH TLS) Passphrase for the private key used for SSH or TLS. If --pass is provided several times, the last set value is used. Example: curl --pass secret --key file https://example.com See also --key and -u, --user.

Do not handle sequences of /../ or /./ in the given URL path. Normally curl squashes or merges them according to standards but with this option set you tell it not to do that. Providing --path-as-is multiple times has no extra effect. Disable it again with --no-path-as-is. Example: curl --path-as-is https://example.com/../../etc/passwd See also --request-target.

(TLS) Use the specified public key file (or hashes) to verify the peer. This can be a path to a file which contains a single public key in PEM or DER format, or any number of base64 encoded sha256 hashes preceded by 'sha256//' and separated by ';'. When negotiating a TLS or SSL connection, the server sends a certificate indicating its identity. A public key is extracted from this certificate and if it does not exactly match the public key provided to this option, curl aborts the connection before sending or receiving any data. This option is independent of option -k, --insecure. If you use bot

(HTTP) Respect RFC 7231/6.4.2 and do not convert POST requests into GET requests when following a 301 redirect. The non-RFC behavior is ubiquitous in web browsers, so curl does the conversion by default to maintain consistency. However, a server may require a POST to remain a POST after such a redirection. This option is meaningful only when using -L, --location. Providing --post301 multiple times has no extra effect. Disable it again with --no-post301. Example: curl --post301 --location -d "data" https://example.com See also --post302, --post303 and -L, --location.

(HTTP) Respect RFC 7231/6.4.3 and do not convert POST requests into GET requests when following a 302 redirect. The non-RFC behavior is ubiquitous in web browsers, so curl does the conversion by default to maintain consistency. However, a server may require a POST to remain a POST after such a redirection. This option is meaningful only when using -L, --location. Providing --post302 multiple times has no extra effect. Disable it again with --no-post302. Example: curl --post302 --location -d "data" https://example.com See also --post301, --post303 and -L, --location.

(HTTP) Violate RFC 7231/6.4.4 and do not convert POST requests into GET requests when following 303 redirect. A server may require a POST to remain a POST after a 303 redirection. This option is meaningful only when using -L, --location. Providing --post303 multiple times has no extra effect. Disable it again with --no-post303. Example: curl --post303 --location -d "data" https://example.com See also --post302, --post301 and -L, --location.

Use the specified SOCKS proxy before connecting to an HTTP or HTTPS -x, --proxy. In such a case curl first connects to the SOCKS proxy and then connects (through SOCKS) to the HTTP or HTTPS proxy. Hence pre proxy. The pre proxy string should be specified with a protocol:// prefix to specify alternative proxy protocols. Use socks4://, socks4a://, socks5:// or socks5h:// to request the specific SOCKS version to be used. No protocol specified makes curl default to SOCKS4. If the port number is not specified in the proxy string, it is assumed to be 1080. User and password that might be provided in

Make curl display transfer progress as a simple progress bar instead of the standard, more informational, meter. This progress bar draws a single line of '#' characters across the screen and shows a percentage if the transfer size is known. For transfers without a known size, there is a space ship (-=o=-) that moves back and forth but only while data is being transferred, with a set of flying hash sign symbols on top. This option is global and does not need to be specified for each use of --next. Providing --progress-bar multiple times has no extra effect. Disable it again with --no-progress-b

Limit what protocols to allow for transfers. Protocols are evaluated left to right, are comma separated, and are each a protocol name or 'all', optionally prefixed by zero or more modifiers. Available modifiers are:

Use protocol for any provided URL missing a scheme. An unknown or unsupported protocol causes error CURLE_UNSUPPORTED_PROTOCOL. This option does not change the default proxy protocol (http). Without this option set, curl guesses protocol based on the hostname, see --url for details. If --proto-default is provided several times, the last set value is used. Example: curl --proto-default https ftp.example.com See also --proto and --proto-redir.

Limit what protocols to allow on redirects. Protocols denied by --proto are not overridden by this option. See --proto for how protocols are represented. Example, allow only HTTP and HTTPS on redirect: curl --proto-redir -all,http,https http://example.com By default curl only allows HTTP, HTTPS, FTP and FTPS on redirects (added in 7.65.2). Specifying all or +all enables all protocols on redirects, which is not good for security. If --proto-redir is provided several times, the last set value is used. Example: curl --proto-redir =http,https https://example.com See also --proto.

Use the specified proxy. The proxy string can be specified with a protocol:// prefix. No protocol specified or http:// it is treated as an HTTP proxy. Use socks4://, socks4a://, socks5:// or socks5h:// to request a specific SOCKS version to be used. Unix domain sockets are supported for socks proxy. Set localhost for the host part. e.g. socks5h://localhost/path/to/socket.sock HTTPS proxy support works with the https:// protocol prefix for OpenSSL and GnuTLS. It also works for BearSSL, mbedTLS, Rustls, Schannel, Secure Transport and wolfSSL (added in 7.87.0). Unrecognized and unsupported proxy

Automatically pick a suitable authentication method when communicating with the given HTTP proxy. This might cause an extra request/response round-trip. Providing --proxy-anyauth multiple times has no extra effect. Example: curl --proxy-anyauth --proxy-user user:passwd -x proxy https://example.com See also -x, --proxy, --proxy-basic and --proxy-digest.

Use HTTP Basic authentication when communicating with the given proxy. Use --basic for enabling HTTP Basic with a remote host. Basic is the default authentication method curl uses with proxies. Providing --proxy-basic multiple times has no extra effect. Example: curl --proxy-basic --proxy-user user:passwd -x proxy https://example.com See also -x, --proxy, --proxy-anyauth and --proxy-digest.

(TLS) Use the operating system's native CA store for certificate verification of the HTTPS proxy. This option is independent of other HTTPS proxy CA certificate locations set at run time or build time. Those locations are searched in addition to the native CA store. Equivalent to --ca-native but used in HTTPS proxy context. Refer to --ca-native for TLS backend limitations. Providing --proxy-ca-native multiple times has no extra effect. Disable it again with --no-proxy-ca-native. Example: curl --proxy-ca-native https://example.com Added in 8.2.0. See also --ca-native, --cacert, --capath, --dump

Use the specified certificate file to verify the HTTPS proxy. The file may contain multiple CA certificates. The certificate(s) must be in PEM format. This allows you to use a different trust for the proxy compared to the remote server connected to via the proxy. Equivalent to --cacert but used in HTTPS proxy context. If --proxy-cacert is provided several times, the last set value is used. Example: curl --proxy-cacert CA-file.txt -x https://proxy https://example.com See also --proxy-capath, --cacert, --capath, --dump-ca-embed and -x, --proxy.

Same as --capath but used in HTTPS proxy context. Use the specified certificate directory to verify the proxy. Multiple paths can be provided by separating them with colon (":") (e.g. "path1:path2:path3"). The certificates must be in PEM format, and if curl is built against OpenSSL, the directory must have been processed using the c_rehash utility supplied with OpenSSL. Using --proxy-capath can allow OpenSSL-powered curl to make SSL-connections much more efficiently than using --proxy-cacert if the --proxy-cacert file contains many CA certificates. If this option is set, the default capath val

Use the specified client certificate file when communicating with an HTTPS proxy. The certificate must be in PKCS#12 format if using Secure Transport, or PEM format if using any other engine. If the optional password is not specified, it is queried for on the terminal. Use --proxy-key to provide the private key. This option is the equivalent to -E, --cert but used in HTTPS proxy context. If --proxy-cert is provided several times, the last set value is used. Example: curl --proxy-cert file -x https://proxy https://example.com See also -x, --proxy, --proxy-key and --proxy-cert-type.

Set type of the provided client certificate when using HTTPS proxy. PEM, DER, ENG, PROV and P12 are recognized types. The default type depends on the TLS backend and is usually PEM, however for Secure Transport and Schannel it is P12. If --proxy-cert is a pkcs11: URI then ENG or PROV is the default type (depending on OpenSSL version). Equivalent to --cert-type but used in HTTPS proxy context. If --proxy-cert-type is provided several times, the last set value is used. Example: curl --proxy-cert-type PEM --proxy-cert file -x https://proxy https://example.com See also --proxy-cert and --proxy-key

(TLS) Same as --ciphers but used in HTTPS proxy context. Specify which cipher suites to use in the connection to your HTTPS proxy when it negotiates TLS 1.2 (1.1, 1.0). The list of ciphers suites must specify valid ciphers. Read up on cipher suite details on this URL: https://curl.se/docs/ssl-ciphers.html If --proxy-ciphers is provided several times, the last set value is used. Example: curl --proxy-ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256 -x https://proxy https://example.com See also --proxy-tls13-ciphers, --ciphers and -x, --proxy.

Provide filename for a PEM formatted file with a Certificate Revocation List that specifies peer certificates that are considered revoked when communicating with an HTTPS proxy. Equivalent to --crlfile but only used in HTTPS proxy context. If --proxy-crlfile is provided several times, the last set value is used. Example: curl --proxy-crlfile rejects.txt -x https://proxy https://example.com See also --crlfile and -x, --proxy.

Use HTTP Digest authentication when communicating with the given proxy. Use --digest for enabling HTTP Digest with a remote host. Providing --proxy-digest multiple times has no extra effect. Example: curl --proxy-digest --proxy-user user:passwd -x proxy https://example.com See also -x, --proxy, --proxy-anyauth and --proxy-basic.

(HTTP) Extra header to include in the request when sending HTTP to a proxy. You may specify any number of extra headers. This is the equivalent option to -H, --header but is for proxy communication only like in CONNECT requests when you want a separate header sent to the proxy to what is sent to the actual remote host. curl makes sure that each header you add/replace is sent with the proper end-of-line marker, you should thus not add that as a part of the header content: do not add newlines or carriage returns, they only mess things up for you. Headers specified with this option are not includ

(HTTP) Negotiate HTTP/2 with an HTTPS proxy. The proxy might still only offer HTTP/1 and then curl sticks to using that version. This has no effect for any other kinds of proxies. Providing --proxy-http2 multiple times has no extra effect. Disable it again with --no-proxy-http2. Example: curl --proxy-http2 -x proxy https://example.com --proxy-http2 requires that libcurl is built to support HTTP/2. Added in 8.1.0. See also -x, --proxy.

Same as -k, --insecure but used in HTTPS proxy context. Every secure connection curl makes is verified to be secure before the transfer takes place. This option makes curl skip the verification step with a proxy and proceed without checking. When this option is not used for a proxy using HTTPS, curl verifies the proxy's TLS certificate before it continues: that the certificate contains the right name which matches the hostname and that the certificate has been signed by a CA certificate present in the cert store. See this online resource for further details: https://curl.se/docs/sslcerts.html

Specify the filename for your private key when using client certificates with your HTTPS proxy. This option is the equivalent to --key but used in HTTPS proxy context. If --proxy-key is provided several times, the last set value is used. Example: curl --proxy-key here -x https://proxy https://example.com See also --proxy-key-type and -x, --proxy.

Specify the private key file type your --proxy-key provided private key uses. DER, PEM, and ENG are supported. If not specified, PEM is assumed. Equivalent to --key-type but used in HTTPS proxy context. If --proxy-key-type is provided several times, the last set value is used. Example: curl --proxy-key-type DER --proxy-key here -x https://proxy https://example.com See also --proxy-key and -x, --proxy.

Use HTTP Negotiate (SPNEGO) authentication when communicating with the given proxy. Use --negotiate for enabling HTTP Negotiate (SPNEGO) with a remote host. Providing --proxy-negotiate multiple times has no extra effect. Example: curl --proxy-negotiate --proxy-user user:passwd -x proxy https://example.com See also --proxy-anyauth, --proxy-basic and --proxy-service-name.

Use HTTP NTLM authentication when communicating with the given proxy. Use --ntlm for enabling NTLM with a remote host. Providing --proxy-ntlm multiple times has no extra effect. Example: curl --proxy-ntlm --proxy-user user:passwd -x http://proxy https://example.com See also --proxy-negotiate, --proxy-anyauth and -U, --proxy-user.

Passphrase for the private key for HTTPS proxy client certificate. Equivalent to --pass but used in HTTPS proxy context. If --proxy-pass is provided several times, the last set value is used. Example: curl --proxy-pass secret --proxy-key here -x https://proxy https://example.com See also -x, --proxy and --proxy-key.

(TLS) Use the specified public key file (or hashes) to verify the proxy. This can be a path to a file which contains a single public key in PEM or DER format, or any number of base64 encoded sha256 hashes preceded by 'sha256//' and separated by ';'. When negotiating a TLS or SSL connection, the server sends a certificate indicating its identity. A public key is extracted from this certificate and if it does not exactly match the public key provided to this option, curl aborts the connection before sending or receiving any data. Before curl 8.10.0 this option did not work due to a bug. If --pro

Set the service name for SPNEGO when doing proxy authentication. If --proxy-service-name is provided several times, the last set value is used. Example: curl --proxy-service-name "shrubbery" -x proxy https://example.com See also --service-name, -x, --proxy and --proxy-negotiate.

Do not work around a security flaw in the TLS1.0 protocol known as BEAST when communicating to an HTTPS proxy. If this option is not used, the TLS layer may use workarounds known to cause interoperability problems with some older server implementations. This option only changes how curl does TLS 1.0 with an HTTPS proxy and has no effect on later TLS versions. WARNING: this option loosens the TLS security, and by using this flag you ask for exactly that. Equivalent to --ssl-allow-beast but used in HTTPS proxy context. Providing --proxy-ssl-allow-beast multiple times has no extra effect. Disable

Same as --ssl-auto-client-cert but used in HTTPS proxy context. This is only supported by Schannel. Providing --proxy-ssl-auto-client-cert multiple times has no extra effect. Disable it again with --no-proxy-ssl-auto-client-cert. Example: curl --proxy-ssl-auto-client-cert -x https://proxy https://example.com Added in 7.77.0. See also --ssl-auto-client-cert and -x, --proxy.

(TLS) Same as --tls13-ciphers but used in HTTPS proxy context. Specify which cipher suites to use in the connection to your HTTPS proxy when it negotiates TLS 1.3. The list of ciphers suites must specify valid ciphers. Read up on TLS 1.3 cipher suite details on this URL: https://curl.se/docs/ssl-ciphers.html This option is used when curl is built to use OpenSSL 1.1.1 or later, Schannel, wolfSSL, or mbedTLS 3.6.0 or later. Before curl 8.10.0 with mbedTLS or wolfSSL, TLS 1.3 cipher suites were set by using the --proxy-ciphers option. If --proxy-tls13-ciphers is provided several times, the last s

Set TLS authentication type with HTTPS proxy. The only supported option is "SRP", for TLS-SRP (RFC 5054). This option works only if the underlying libcurl is built with TLS-SRP support. Equivalent to --tlsauthtype but used in HTTPS proxy context. If --proxy-tlsauthtype is provided several times, the last set value is used. Example: curl --proxy-tlsauthtype SRP -x https://proxy https://example.com See also -x, --proxy, --proxy-tlsuser and --proxy-tlspassword.

Set password to use with the TLS authentication method specified with --proxy-tlsauthtype when using HTTPS proxy. Requires that --proxy-tlsuser is set. This option does not work with TLS 1.3. Equivalent to --tlspassword but used in HTTPS proxy context. If --proxy-tlspassword is provided several times, the last set value is used. Example: curl --proxy-tlspassword passwd -x https://proxy https://example.com See also -x, --proxy and --proxy-tlsuser.

Set username for use for HTTPS proxy with the TLS authentication method specified with --proxy-tlsauthtype. Requires that --proxy-tlspassword also is set. This option does not work with TLS 1.3. If --proxy-tlsuser is provided several times, the last set value is used. Example: curl --proxy-tlsuser smith -x https://proxy https://example.com See also -x, --proxy and --proxy-tlspassword.

Use at least TLS version 1.x when negotiating with an HTTPS proxy. That means TLS version 1.0 or higher Equivalent to -1, --tlsv1 but for an HTTPS proxy context. Providing --proxy-tlsv1 multiple times has no extra effect. Example: curl --proxy-tlsv1 -x https://proxy https://example.com See also -x, --proxy.

Specify the username and password to use for proxy authentication. If you use a Windows SSPI-enabled curl binary and do either Negotiate or NTLM authentication then you can tell curl to select the username and password from your environment by specifying a single colon with this option: "-U :". On systems where it works, curl hides the given option argument from process listings. This is not enough to protect credentials from possibly getting seen by other users on the same system as they still are visible for a moment before being cleared. Such sensitive data should be retrieved from a file i

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 specifies an HTTP 1.0 protocol instead of the default HTTP 1.1. Providing --proxy1.0 multiple times has no extra effect. Example: curl --proxy1.0 http://proxy https://example.com See also -x, --proxy, --socks5 and --preproxy.

When an HTTP proxy is used -x, --proxy, this option makes curl tunnel the traffic through the proxy. The tunnel approach is made with the HTTP proxy CONNECT request and requires that the proxy allows direct connection 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. Providing --proxytunnel multiple times has no extra effect. Disable it again with --no-proxytunnel. Example: curl --proxytunnel -x http://proxy https://example.com See also -x, --proxy.

(SFTP SCP) Public key filename. Allows you to provide your public key in this separate file. curl attempts to automatically extract the public key from the private key file, so passing this option is generally not required. Note that this public key extraction requires libcurl to be linked against a copy of libssh2 1.2.8 or higher that is itself linked against OpenSSL. If --pubkey is provided several times, the last set value is used. Example: curl --pubkey file.pub sftp://example.com/ See also --pass.

(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 '-'. (FTP only) To make commands be sent after curl has changed the working directory, just before the file transfer command(s), prefix the command with a '+'. This is not performed when a directory listing is performed. You may specify any number of commands. By default curl stops at first failure. To make curl continue

Deprecated option. This option is ignored (added in 7.84.0). Prior to that it only had an effect on curl if built to use old versions of OpenSSL. Specify the path name to file containing random data. The data may be used to seed the random engine for SSL connections. If --random-file is provided several times, the last set value is used. Example: curl --random-file rubbish https://example.com See also --egd-file.

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

Specify the maximum transfer frequency you allow curl to use - in number of transfer starts per time unit (sometimes called request rate). Without this option, curl starts the next transfer as fast as possible. If given several URLs and a transfer completes faster than the allowed rate, curl waits until the next transfer is started to maintain the requested rate. This option has no effect when -Z, --parallel is used. The request rate is provided as "N/U" where N is an integer number and U is a time unit. Supported units are 's' (second), 'm' (minute), 'h' (hour) and 'd' /(day, as in a 24 hour

(HTTP) When used, it disables all internal HTTP decoding of content or transfer encodings and instead makes them passed on unaltered, raw. Providing --raw multiple times has no extra effect. Disable it again with --no-raw. Example: curl --raw https://example.com See also --tr-encoding.

(HTTP) Set the referrer URL in the HTTP request. This can also be set with the -H, --header flag of course. When used with -L, --location you can append ";auto"" to the -e, --referer URL to make curl automatically set the previous URL when it follows a Location: header. The ";auto" string can be used alone, even if you do not set an initial -e, --referer. If --referer is provided several times, the last set value is used. Examples: curl --referer "https://fake.example" https://example.com curl --referer "https://fake.example;auto" -L https://example.com curl --referer ";auto" -L https://exampl

(HTTP) Tell the -O, --remote-name option to use the server-specified Content-Disposition filename instead of extracting a filename from the URL. If the server-provided filename contains a path, that is stripped off before the filename is used. The file is saved in the current directory, or in the directory specified with --output-dir. If the server specifies a filename and a file with that name already exists in the destination directory, it is not overwritten and an error occurs - unless you allow it by using the --clobber option. If the server does not specify a filename then this option has

Write output to a local file named like the remote file we get. (Only the file part of the remote file is used, the path is cut off.) The file is saved in the current working directory. If you want the file saved in a different directory, make sure you change the current working directory before invoking curl with this option or use --output-dir. The remote filename to use for saving is extracted from the given URL, nothing else, and if it already exists it is overwritten. If you want the server to be able to choose the filename refer to -J, --remote-header-name which can be used in addition t

Change the default action for all given URLs to be dealt with as if -O, --remote-name were used for each one. If you want to disable that for a specific URL after --remote-name-all has been used, you must use "-o -" or --no-remote-name. Providing --remote-name-all multiple times has no extra effect. Disable it again with --no-remote-name-all. Example: curl --remote-name-all ftp://example.com/file1 ftp://example.com/file2 See also -O, --remote-name.

Make curl attempt to figure out the timestamp of the remote file that is getting downloaded, and if that is available make the local file get that same timestamp. Providing --remote-time multiple times has no extra effect. Disable it again with --no-remote-time. Example: curl --remote-time -o foo https://example.com See also -O, --remote-name and -z, --time-cond.

Remove the output file if an error occurs. If curl returns an error when told to save output in a local file. This prevents curl from leaving a partial file in the case of an error during transfer. If the output is not a regular file, this option has no effect. The -C, --continue-at option cannot be used together with --remove-on-error. Providing --remove-on-error multiple times has no extra effect. Disable it again with --no-remove-on-error. Example: curl --remove-on-error -o output https://example.com Added in 7.83.0. See also -f, --fail.

Change the method to use when starting the transfer. curl passes on the verbatim string you give it in the request without any filter or other safe guards. That includes white space and control characters.

(HTTP) Use an alternative target (path) instead of using the path as provided in the URL. Particularly useful when wanting to issue HTTP requests without leading slash or other data that does not follow the regular URL pattern, like "OPTIONS *". curl passes on the verbatim string you give it in the request without any filter or other safe guards. That includes white space and control characters. If --request-target is provided several times, the last set value is used. Example: curl --request-target "*" -X OPTIONS https://example.com See also -X, --request.

Provide a custom address for a specific host and port pair. Using this, you can make the curl requests(s) use a specified address and prevent the otherwise normally resolved address to be used. Consider it a sort of /etc/hosts alternative provided on the command line. The port number should be the number used for the specific protocol the host is used for. It means you need several entries if you want to provide addresses for the same host but different ports. By specifying "*" as host you can tell curl to resolve any host and specific port pair to the specified address. Wildcard is resolved l

If a transient error is returned when curl tries to perform a transfer, it retries this number of times before giving up. Setting the number to 0 makes curl do no retries (which is the default). Transient error means either: a timeout, an FTP 4xx response code or an HTTP 408, 429, 500, 502, 503 or 504 response code. When curl is about to retry a transfer, it first waits one second and then for all forthcoming retries it doubles the waiting time until it reaches 10 minutes, which then remains the set fixed delay time between the rest of the retries. By using --retry-delay you disable this expon

Retry on any error. This option is used together with --retry. This option is the "sledgehammer" of retrying. Do not use this option by default (for example in your curlrc), there may be unintended consequences such as sending or receiving duplicate data. Do not use with redirected input or output. You might be better off handling your unique problems in a shell script. Please read the example below. WARNING: For server compatibility curl attempts to retry failed flaky transfers as close as possible to how they were started, but this is not possible with redirected input or output. For example

In addition to the other conditions, consider ECONNREFUSED as a transient error too for --retry. This option is used together with --retry. Providing --retry-connrefused multiple times has no extra effect. Disable it again with --no-retry-connrefused. Example: curl --retry-connrefused --retry 7 https://example.com See also --retry and --retry-all-errors.

Make curl sleep this amount of time before each retry when a transfer has failed with a transient error (it changes the default backoff time algorithm between retries). This option is only interesting if --retry is also used. Setting this delay to zero makes curl use the default backoff time. If --retry-delay is provided several times, the last set value is used. Example: curl --retry-delay 5 --retry 7 https://example.com See also --retry.

The retry timer is reset before the first transfer attempt. Retries are done as usual (see --retry) as long as the timer has not reached this given limit. Notice that if the timer has not reached the limit, the request is made and while performing, it may take longer than this given time period. To limit a single request's maximum time, use -m, --max-time. Set this option to zero to not timeout retries. If --retry-max-time is provided several times, the last set value is used. Example: curl --retry-max-time 30 --retry 10 https://example.com See also --retry.

Use this authorization identity (authzid), during SASL PLAIN authentication, in addition to the authentication identity (authcid) as specified by -u, --user. If the option is not specified, the server derives the authzid from the authcid, but if specified, and depending on the server implementation, it may be used to access another user's inbox, that the user has been granted access to, or a shared mailbox for example. If --sasl-authzid is provided several times, the last set value is used. Example: curl --sasl-authzid zid imap://example.com/ Added in 7.66.0. See also --login-options.

Enable initial response in SASL authentication. Providing --sasl-ir multiple times has no extra effect. Disable it again with --no-sasl-ir. Example: curl --sasl-ir imap://example.com/ See also --sasl-authzid.

Set the service name for SPNEGO. If --service-name is provided several times, the last set value is used. Example: curl --service-name sockd/server https://example.com See also --negotiate and --proxy-service-name.

When used with -s, --silent, it makes curl show an error message if it fails. This option is global and does not need to be specified for each use of --next. Providing --show-error multiple times has no extra effect. Disable it again with --no-show-error. Example: curl --show-error --silent https://example.com See also --no-progress-meter.

(HTTP FTP) Show response headers in the output. HTTP response headers can include things like server name, cookies, date of the document, HTTP version and more. With non-HTTP protocols, the "headers" are other server communication. This option makes the response headers get saved in the same stream/output as the data. -D, --dump-header exists to save headers in a separate stream. To view the request headers, consider the -v, --verbose option. Prior to 7.75.0 curl did not print the headers if -f, --fail was used in combination with this option and there was an error reported by the server. This

(TLS) Set specific signature algorithms to use during SSL session establishment according to RFC 5246, 7.4.1.4.1. An algorithm can use either a signature algorithm and a hash algorithm pair separated by a "+" (e.g. "ECDSA+SHA224"), or its TLS 1.3 signature scheme name (e.g. "ed25519"). Multiple algorithms can be provided by separating them with ":" (e.g. "DSA+SHA256:rsa_pss_pss_sha256"). The parameter is available as "-sigalgs" in the OpenSSL "s_client" and "s_server" utilities. "--sigalgs" allows a OpenSSL powered curl to make SSL-connections with exactly the signature algorithms requested by

Silent or quiet mode. Do not show progress meter or error messages. Makes curl mute. It still outputs the data you ask for, potentially even to the terminal/stdout unless you redirect it. Use -S, --show-error in addition to this option to disable progress meter but still show error messages. Providing --silent multiple times has no extra effect. Disable it again with --no-silent. Example: curl -s https://example.com See also -v, --verbose, --stderr and --no-progress-meter.

If there is a local file present when a download is requested, the operation is skipped. Note that curl cannot know if the local file was previously downloaded fine, or if it is incomplete etc, it just knows if there is a filename present in the file system or not and it skips the transfer if it is. Providing --skip-existing multiple times has no extra effect. Disable it again with --no-skip-existing. Example: curl --skip-existing --output local/dir/file https://example.com Added in 8.10.0. See also -o, --output, -O, --remote-name and --no-clobber.

Use the specified SOCKS4 proxy. If the port number is not specified, it is assumed at port 1080. Using this socket type makes curl resolve the hostname and pass the address on to the proxy. To specify proxy on a Unix domain socket, use localhost for host, e.g. "socks4://localhost/path/to/socket.sock" This option overrides any previous use of -x, --proxy, as they are mutually exclusive. This option is superfluous since you can specify a socks4 proxy with -x, --proxy using a socks4:// protocol prefix. --preproxy can be used to specify a SOCKS proxy at the same time proxy is used with an HTTP/HTT

Use the specified SOCKS4a proxy. If the port number is not specified, it is assumed at port 1080. This asks the proxy to resolve the hostname. To specify proxy on a Unix domain socket, use localhost for host, e.g. "socks4a://localhost/path/to/socket.sock" This option overrides any previous use of -x, --proxy, as they are mutually exclusive. This option is superfluous since you can specify a socks4a proxy with -x, --proxy using a socks4a:// protocol prefix. --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 c

Use the specified SOCKS5 proxy - but resolve the hostname locally. If the port number is not specified, it is assumed at port 1080. To specify proxy on a Unix domain socket, use localhost for host, e.g. "socks5://localhost/path/to/socket.sock" This option overrides any previous use of -x, --proxy, as they are mutually exclusive. This option is superfluous since you can specify a socks5 proxy with -x, --proxy using a socks5:// protocol prefix. --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

Use username/password authentication when connecting to a SOCKS5 proxy. The username/password authentication is enabled by default. Use --socks5-gssapi to force GSS-API authentication to SOCKS5 proxies. Providing --socks5-basic multiple times has no extra effect. Example: curl --socks5-basic --socks5 hostname:4096 https://example.com See also --socks5.

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. Providing --socks5-gssapi multiple times has no extra effect. Disable it again with --no-socks5-gssapi. Example: curl --socks5-gssapi --socks5 hostname:4096 https://example.com See also --socks5.

As part of the GSS-API negotiation a protection mode is negotiated. RFC 1961 says in section 4.3/4.4 it should be protected, but the NEC reference implementation does not. The option --socks5-gssapi-nec allows the unprotected exchange of the protection mode negotiation. Providing --socks5-gssapi-nec multiple times has no extra effect. Disable it again with --no-socks5-gssapi-nec. Example: curl --socks5-gssapi-nec --socks5 hostname:4096 https://example.com See also --socks5.

Set the service name for a socks server. Default is rcmd/server-fqdn. If --socks5-gssapi-service is provided several times, the last set value is used. Example: curl --socks5-gssapi-service sockd --socks5 hostname:4096 https://example.com See also --socks5.

Use the specified SOCKS5 proxy (and let the proxy resolve the hostname). If the port number is not specified, it is assumed at port 1080. To specify proxy on a Unix domain socket, use localhost for host, e.g. "socks5h://localhost/path/to/socket.sock" This option overrides any previous use of -x, --proxy, as they are mutually exclusive. This option is superfluous since you can specify a socks5 hostname proxy with -x, --proxy using a socks5h:// protocol prefix. --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 firs

If a transfer is slower than this set speed (in bytes per second) for a given number of seconds, it gets aborted. The time period is set with -y, --speed-time and is 30 seconds by default. If --speed-limit is provided several times, the last set value is used. Example: curl --speed-limit 300 --speed-time 10 https://example.com See also -y, --speed-time, --limit-rate and -m, --max-time.

If a transfer runs slower than speed-limit bytes per second during a speed-time period, the transfer is aborted. If speed-time is used, the default speed-limit is 1 unless set with -Y, --speed-limit. This option controls transfers (in both directions) but does not affect slow connects etc. If this is a concern for you, try the --connect-timeout option. If --speed-time is provided several times, the last set value is used. Example: curl --speed-limit 300 --speed-time 10 https://example.com See also -Y, --speed-limit and --limit-rate.

(FTP IMAP POP3 SMTP LDAP) Warning: this is considered an insecure option. Consider using --ssl-reqd instead to be sure curl upgrades to a secure connection. Try to use SSL/TLS for the connection - often referred to as STARTTLS or STLS because of the involved commands. Reverts to a non-secure connection if the server does not support SSL/TLS. See also --ftp-ssl-control and --ssl-reqd for different levels of encryption required. This option is handled in LDAP (added in 7.81.0). It is fully supported by the OpenLDAP backend and ignored by the generic ldap backend. Please note that a server may cl

(TLS) Do not work around a security flaw in the TLS1.0 protocol known as BEAST. If this option is not used, the TLS layer may use workarounds known to cause interoperability problems with some older server implementations. This option only changes how curl does TLS 1.0 and has no effect on later TLS versions. WARNING: this option loosens the TLS security, and by using this flag you ask for exactly that. Providing --ssl-allow-beast multiple times has no extra effect. Disable it again with --no-ssl-allow-beast. Example: curl --ssl-allow-beast https://example.com See also --proxy-ssl-allow-beast

(TLS) (Schannel) Automatically locate and use a client certificate for authentication, when requested by the server. Since the server can request any certificate that supports client authentication in the OS certificate store it could be a privacy violation and unexpected. Providing --ssl-auto-client-cert multiple times has no extra effect. Disable it again with --no-ssl-auto-client-cert. Example: curl --ssl-auto-client-cert https://example.com Added in 7.77.0. See also --proxy-ssl-auto-client-cert.

(TLS) (Schannel) Disable certificate revocation checks. WARNING: this option loosens the SSL security, and by using this flag you ask for exactly that. Providing --ssl-no-revoke multiple times has no extra effect. Disable it again with --no-ssl-no-revoke. Example: curl --ssl-no-revoke https://example.com See also --crlfile.

(FTP IMAP POP3 SMTP LDAP) Require SSL/TLS for the connection - often referred to as STARTTLS or STLS because of the involved commands. Terminates the connection if the transfer cannot be upgraded to use SSL/TLS. This option is handled in LDAP (added in 7.81.0). It is fully supported by the OpenLDAP backend and rejected by the generic ldap backend if explicit TLS is required. This option is unnecessary if you use a URL scheme that in itself implies immediate and implicit use of TLS, like for FTPS, IMAPS, POP3S, SMTPS and LDAPS. Such a transfer always fails if the TLS handshake does not work. Th

(TLS) (Schannel) Ignore certificate revocation checks when they failed due to missing/offline distribution points for the revocation check lists. Providing --ssl-revoke-best-effort multiple times has no extra effect. Disable it again with --no-ssl-revoke-best-effort. Example: curl --ssl-revoke-best-effort https://example.com Added in 7.70.0. See also --crlfile and -k, --insecure.

(TLS) Use the given file to load SSL session tickets into curl's cache before starting any transfers. At the end of a successful curl run, the cached SSL sessions tickets are saved to the file, replacing any previous content. The file does not have to exist, but curl reports an error if it is unable to create it. Unused loaded tickets are saved again, unless they get replaced or purged from the cache for space reasons. Using a session file allows "--tls-earlydata" to send the first request in "0-RTT" mode, should an SSL session with the feature be found. Note that a server may not support earl

(SSL) This option previously asked curl to use SSLv2, but is now ignored (added in 7.77.0). SSLv2 is widely considered insecure (see RFC 6176). Providing --sslv2 multiple times has no extra effect. Example: curl --sslv2 https://example.com -2, --sslv2 requires that libcurl is built to support TLS. This option is mutually exclusive with -3, --sslv3, -1, --tlsv1, --tlsv1.1 and --tlsv1.2. See also --http1.1 and --http2.

(SSL) This option previously asked curl to use SSLv3, but is now ignored (added in 7.77.0). SSLv3 is widely considered insecure (see RFC 7568). Providing --sslv3 multiple times has no extra effect. Example: curl --sslv3 https://example.com -3, --sslv3 requires that libcurl is built to support TLS. This option is mutually exclusive with -2, --sslv2, -1, --tlsv1, --tlsv1.1 and --tlsv1.2. See also --http1.1 and --http2.

Redirect all writes to stderr to the specified file instead. If the filename is a plain '-', it is instead written to stdout. This option is global and does not need to be specified for each use of --next. If --stderr is provided several times, the last set value is used. Example: curl --stderr output.txt https://example.com See also -v, --verbose and -s, --silent.

Enable automatic use of bold font styles when writing HTTP headers to the terminal. Use --no-styled-output to switch them off. Styled output requires a terminal that supports bold fonts. This feature is not present on curl for Windows due to lack of this capability. This option is global and does not need to be specified for each use of --next. Providing --styled-output multiple times has no extra effect. Disable it again with --no-styled-output. Example: curl --styled-output -I https://example.com Added in 7.61.0. See also -I, --head and -v, --verbose.

When -p, --proxytunnel is used and a CONNECT request is made, do not output proxy CONNECT response headers. This option is meant to be used with -D, --dump-header or -i, --show-headers which are used to show protocol headers in the output. It has no effect on debug options such as -v, --verbose or --trace, or any statistics. Providing --suppress-connect-headers multiple times has no extra effect. Disable it again with --no-suppress-connect-headers. Example: curl --suppress-connect-headers --show-headers -x proxy https://example.com See also -D, --dump-header, -i, --show-headers and -p, --proxy

Enable use of TCP Fast Open (RFC 7413). TCP Fast Open is a TCP extension that allows data to be sent earlier over the connection (before the final handshake ACK) if the client and server have been connected previously. Providing --tcp-fastopen multiple times has no extra effect. Disable it again with --no-tcp-fastopen. Example: curl --tcp-fastopen https://example.com See also --false-start.

Turn on the TCP_NODELAY option. See the curl_easy_setopt(3) man page for details about this option. curl sets this option by default and you need to explicitly switch it off if you do not want it on. Providing --tcp-nodelay multiple times has no extra effect. Disable it again with --no-tcp-nodelay. Example: curl --tcp-nodelay https://example.com See also -N, --no-buffer.

Pass options to the telnet protocol. Supported options are:

(TFTP) Set the TFTP BLKSIZE option (must be 512 or larger). This is the block size that curl tries to use when transferring data to or from a TFTP server. By default 512 bytes are used. If --tftp-blksize is provided several times, the last set value is used. Example: curl --tftp-blksize 1024 tftp://example.com/file See also --tftp-no-options.

(TFTP) Do not send TFTP options requests. This improves interop with some legacy servers that do not acknowledge or properly implement TFTP options. When this option is used --tftp-blksize is ignored. Providing --tftp-no-options multiple times has no extra effect. Disable it again with --no-tftp-no-options. Example: curl --tftp-no-options tftp://192.168.0.1/ See also --tftp-blksize.

(HTTP FTP) Request a file that has been modified later than the given time and date, or one that has been modified before that time. The date expression can be all sorts of date strings or if it does not match any internal ones, it is treated as a filename and curl tries to get the modification date (mtime) from that file instead. See the curl_getdate(3) man pages for date expression details. Start the date expression with a dash (-) to make it request for a document that is older than the given date/time, default is a document that is newer than the specified date/time. If provided a non-exis

(TLS) Enable the use of TLSv1.3 early data, also known as '0RTT' where possible. This has security implications for the requests sent that way. This option is used when curl is built to use GnuTLS. If a server supports this TLSv1.3 feature, and to what extent, is announced as part of the TLS "session" sent back to curl. Until curl has seen such a session in a previous request, early data cannot be used. When a new connection is initiated with a known TLSv1.3 session, and that session announced early data support, the first request on this connection is sent before the TLS handshake is complete

(TLS) Set the maximum allowed TLS version. The minimum acceptable version is set by tlsv1.0, tlsv1.1, tlsv1.2 or tlsv1.3. If the connection is done without TLS, this option has no effect. This includes QUIC-using (HTTP/3) transfers.

(TLS) Set which cipher suites to use in the connection if it negotiates TLS 1.3. The list of ciphers suites must specify valid ciphers. Read up on TLS 1.3 cipher suite details on this URL: https://curl.se/docs/ssl-ciphers.html This option is used when curl is built to use OpenSSL 1.1.1 or later, wolfSSL, or mbedTLS 3.6.0 or later. Before curl 8.10.0 with mbedTLS or wolfSSL, TLS 1.3 cipher suites were set by using the --ciphers option. If --tls13-ciphers is provided several times, the last set value is used. Example: curl --tls13-ciphers TLS_AES_128_GCM_SHA256 https://example.com Added in 7.61.

(TLS) Set TLS authentication type. Currently, the only supported option is "SRP", for TLS-SRP (RFC 5054). If --tlsuser and --tlspassword are specified but --tlsauthtype is not, then this option defaults to "SRP". This option works only if the underlying libcurl is built with TLS-SRP support, which requires OpenSSL or GnuTLS with TLS-SRP support. If --tlsauthtype is provided several times, the last set value is used. Example: curl --tlsauthtype SRP https://example.com See also --tlsuser.

(TLS) Set password to use with the TLS authentication method specified with --tlsauthtype. Requires that --tlsuser is set. This option does not work with TLS 1.3. If --tlspassword is provided several times, the last set value is used. Example: curl --tlspassword pwd --tlsuser user https://example.com See also --tlsuser.

(TLS) Set username for use with the TLS authentication method specified with --tlsauthtype. Requires that --tlspassword also is set. This option does not work with TLS 1.3. If --tlsuser is provided several times, the last set value is used. Example: curl --tlspassword pwd --tlsuser user https://example.com See also --tlspassword.

(TLS) Use at least TLS version 1.x when negotiating with a remote TLS server. That means TLS version 1.0 or higher Providing --tlsv1 multiple times has no extra effect. Example: curl --tlsv1 https://example.com -1, --tlsv1 requires that libcurl is built to support TLS. This option is mutually exclusive with --tlsv1.1, --tlsv1.2 and --tlsv1.3. See also --http1.1 and --http2.

(TLS) Force curl to use TLS version 1.0 or later when connecting to a remote TLS server. In old versions of curl this option was documented to allow _only_ TLS 1.0. That behavior was inconsistent depending on the TLS library. Use --tls-max if you want to set a maximum TLS version. Providing --tlsv1.0 multiple times has no extra effect. Example: curl --tlsv1.0 https://example.com See also --tlsv1.3.

(TLS) Force curl to use TLS version 1.1 or later when connecting to a remote TLS server. In old versions of curl this option was documented to allow _only_ TLS 1.1. That behavior was inconsistent depending on the TLS library. Use --tls-max if you want to set a maximum TLS version. Providing --tlsv1.1 multiple times has no extra effect. Example: curl --tlsv1.1 https://example.com See also --tlsv1.3 and --tls-max.

(TLS) Force curl to use TLS version 1.2 or later when connecting to a remote TLS server. In old versions of curl this option was documented to allow _only_ TLS 1.2. That behavior was inconsistent depending on the TLS library. Use --tls-max if you want to set a maximum TLS version. Providing --tlsv1.2 multiple times has no extra effect. Example: curl --tlsv1.2 https://example.com See also --tlsv1.3 and --tls-max.

(TLS) Force curl to use TLS version 1.3 or later when connecting to a remote TLS server. If the connection is done without TLS, this option has no effect. This includes QUIC-using (HTTP/3) transfers. Note that TLS 1.3 is not supported by all TLS backends. Providing --tlsv1.3 multiple times has no extra effect. Example: curl --tlsv1.3 https://example.com See also --tlsv1.2 and --tls-max.

(HTTP) Request a compressed Transfer-Encoding response using one of the algorithms curl supports, and uncompress the data while receiving it. Providing --tr-encoding multiple times has no extra effect. Disable it again with --no-tr-encoding. Example: curl --tr-encoding https://example.com See also --compressed.

Save a full trace dump of all incoming and outgoing data, including descriptive information, in the given output file. Use "-" as filename to have the output sent to stdout. Use "%" as filename to have the output sent to stderr. Note that verbose output of curl activities and network traffic might contain sensitive data, including usernames, credentials or secret data content. Be aware and be careful when sharing trace logs with others. This option is global and does not need to be specified for each use of --next. If --trace is provided several times, the last set value is used. Example: curl

Save a full trace dump of all incoming and outgoing data, including descriptive information, in the given output file. Use "-" as filename to have the output sent to stdout. Use "%" as filename to send the output to stderr. This is similar to --trace, but leaves out the hex part and only shows the ASCII part of the dump. It makes smaller output that might be easier to read for untrained humans. Note that verbose output of curl activities and network traffic might contain sensitive data, including usernames, credentials or secret data content. Be aware and be careful when sharing trace logs wit

Set configuration for trace output. A comma-separated list of components where detailed output can be made available from. Names are case-insensitive. Specify 'all' to enable all trace components. In addition to trace component names, specify "ids" and "time" to avoid extra --trace-ids or --trace-time parameters. See the curl_global_trace(3) man page for more details. This option is global and does not need to be specified for each use of --next. --trace-config can be used several times in a command line Example: curl --trace-config ids,http/2 https://example.com Added in 8.3.0. See also -v, -

Prepend the transfer and connection identifiers to each trace or verbose line that curl displays. This option is global and does not need to be specified for each use of --next. Providing --trace-ids multiple times has no extra effect. Disable it again with --no-trace-ids. Example: curl --trace-ids --trace-ascii output https://example.com Added in 8.2.0. See also --trace and -v, --verbose.

Prepend a time stamp to each trace or verbose line that curl displays. This option is global and does not need to be specified for each use of --next. Providing --trace-time multiple times has no extra effect. Disable it again with --no-trace-time. Example: curl --trace-time --trace-ascii output https://example.com See also --trace and -v, --verbose.

(HTTP) Connect through this Unix domain socket, instead of using the network. If --unix-socket is provided several times, the last set value is used. Example: curl --unix-socket socket-path https://example.com See also --abstract-unix-socket.

Upload the specified local file to the remote URL. If there is no file part in the specified URL, curl appends the local file name to the end of the URL before the operation starts. You must use a trailing slash (/) on the last directory to prove to curl that there is no filename or curl thinks that your last directory name is the remote filename to use. When putting the local filename at the end of the URL, curl ignores what is on the left side of any slash (/) or backslash (\\) used in the filename and only appends what is on the right side of the rightmost such character. Use the filename "

Specify additional behavior to apply to uploaded files. Flags are specified as either a single flag value or a comma-separated list of flag values. These values are case-sensitive and may be negated by prepending them with a '-' character. Currently the following flag values are accepted: answered, deleted, draft, flagged, and seen. The currently-accepted flag values are used to set flags on IMAP uploads. If --upload-flags is provided several times, the last set value is used. Example: curl --upload-flags Flagged,!Seen --upload-file local/dir/file https://example.com Added in 8.13.0. See also

Specify a URL to fetch or send data to. If the given URL is missing a scheme (such as "http://" or "ftp://" etc) curl guesses which scheme to use based on the hostname. If the outermost subdomain name matches DICT, FTP, IMAP, LDAP, POP3 or SMTP case insensitively, then that protocol is used, otherwise it assumes HTTP. Scheme guessing can be avoided by providing a full URL including the scheme, or disabled by setting a default protocol, see --proto-default for details. To control where the contents of a retrieved URL is written instead of the default stdout, use the -o, --output or the -O, --re

(all) Add a piece of data, usually a name + value pair, to the end of the URL query part. The syntax is identical to that used for --data-urlencode with one extension: If the argument starts with a '+' (plus), the rest of the string is provided as-is unencoded. The query part of a URL is the one following the question mark on the right end. --url-query can be used several times in a command line Examples: curl --url-query name=val https://example.com curl --url-query =encodethis http://example.net/foo curl --url-query name@file https://example.com curl --url-query @fileonly https://example.com

(FTP LDAP) Enable ASCII transfer mode. For FTP, this can also be enforced by using a URL that ends with ";type=A". This option causes data sent to stdout to be in text mode for Win32 systems. Providing --use-ascii multiple times has no extra effect. Disable it again with --no-use-ascii. Example: curl -B ftp://example.com/README See also --crlf and --data-ascii.

Specify the username and password to use for server authentication. Overrides -n, --netrc and --netrc-optional. If you simply specify the username, curl prompts for a password. The username and passwords are split up on the first colon, which makes it impossible to use a colon in the username with this option. The password can, still. On systems where it works, curl hides the given option argument from process listings. This is not enough to protect credentials from possibly getting seen by other users on the same system as they still are visible for a moment before being cleared. Such sensiti

(HTTP) Specify the User-Agent string to send to the HTTP server. To encode blanks in the string, surround the string with single quote marks. This header can also be set with the -H, --header or the --proxy-header options. If you give an empty argument to -A, --user-agent (""), it removes the header completely from the request. If you prefer a blank header, you can set it to a single space (" "). By default, curl uses curl/VERSION, such as User-Agent: curl/8.14.1. If --user-agent is provided several times, the last set value is used. Example: curl -A "Agent 007" https://example.com See also -H

Set a variable with "name=content" or "name@file" (where "file" can be stdin if set to a single dash ("-")). The name is a case sensitive identifier that must consist of no other letters than a-z, A-Z, 0-9 or underscore. The specified content is then associated with this identifier. Setting the same variable name again overwrites the old contents with the new. The contents of a variable can be referenced in a later command line option when that option name is prefixed with "--expand-", and the name is used as "{{name}}". --variable can import environment variables into the name space. Opt to e

Make curl output verbose information during the operation. Useful for debugging and seeing what's going on under the hood. A line starting with > means header data sent by curl, < means header data received by curl that is hidden in normal cases, and a line starting with * means additional info provided by curl. If you only want HTTP headers in the output, -i, --show-headers or -D, --dump-header might be more suitable options. Since curl 8.10, mentioning this option several times in the same argument increases the level of the trace output. However, as before, a single -v, --verbose or --no-ve

Display 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. This line may contain one or more TLS libraries. curl can be built to support more than one TLS library which then makes curl - at start-up - select which particular backend to use for this invocation. If curl supports more than one TLS library like this, the ones that are not selected by default are listed within parentheses. Thus, if you do not specify which backend to use (with the "CURL_SSL_BACKEND" environment v

(All) Set VLAN priority as defined in IEEE 802.1Q. This field is set on Ethernet level, and only works within a local network. The valid range for <priority> is 0 to 7. If --vlan-priority is provided several times, the last set value is used. Example: curl --vlan-priority 4 https://example.com Added in 8.9.0. See also --ip-tos.

Make curl display information on stdout after a completed transfer. The format is a string that may contain plain text mixed with any number of variables. The format can be specified as a literal "string", or you can have curl read the format from a file with "@filename" and to tell curl to read the format from stdin you write "@-". The variables present in the output format are substituted by the value or text that curl thinks fit, as described below. All variables are specified as %{variable_name} and to output a normal % you just write them as %%. You can output a newline by using \n, a car

Store metadata in the extended file attributes. When saving output to a file, tell curl to store file metadata in extended file attributes. Currently, "curl" is stored in the "creator" attribute, the URL is stored in the "xdg.origin.url" attribute and, for HTTP, the content type is stored in the "mime_type" attribute. If the file system does not support extended attributes, a warning is issued. Providing --xattr multiple times has no extra effect. Disable it again with --no-xattr. Example: curl --xattr -o storage https://example.com See also -R, --remote-time, -w, --write-out and -v, --verbose