CURL command Tutorial in Linux with Example Usage

NAME

curl - Transfers data from or to a server, using one of the protocols: HTTP, HTTPS, FTP, FTPS, SCP, SFTP, TFTP, DICT, TELNET, LDAP or FILE. (To transfer multiple files use wget or FTP.)

SYNOPSIS

curl [options] [URL...]

DESCRIPTION

Curl transfers data from or to a server, using one of the protocols: HTTP, HTTPS, FTP, FTPS, SCP, SFTP, TFTP, DICT, TELNET, LDAP or FILE. (To transfer multiple files use wget or FTP.).

OPTIONS

Maximum time that you allow the whole operation to take. This is useful for preventing your batch jobs from hanging for hours due to slow networks or links going down. See also the --connect-timeout option.

Tag	Description
url	One or multiple URLs that will be fetched in sequence. Multiple URLs or parts of URLs can be specified by writing part sets within braces as in: http://site.{one,two,three}.com or get sequences of alphanumeric series by using [] as in: ftp://ftp.numericals.com/file[1-100].txt ftp://ftp.numericals.com/file[001-100].txt (with leading zeros) ftp://ftp.letters.com/file[a-z].txt
-A "agent string" --user-agent "agent string"	Specify the User-Agent string to send to the HTTP server. To encode blanks in the string, surround the string with single quote marks. This can also be set with -H, --header option. (HTTP)
-b name=data --cookie name=data	Send the data to the HTTP server as a cookie. It is supposedly the data previously received from the server in a "Set-Cookie:" line. The data should be in the format "NAME1=VALUE1; NAME2=VALUE2".
-c filename --cookie-jar file name	Save cookies to file after a completed operation. Curl writes all cookies previously read from a specified file as well as all cookies received from remote server(s). If no cookies are known, no file will be written. To write to stdout, set the file name to a single dash, "-".
--compressed	Request a compressed response using one of the algorithms curl supports (gzip), and save the uncompressed document. If this option is used and the server sends an unsupported encoding, curl will report an error.(HTTP)
-d @file -d "string" --data "string"	Send the specified data in an (HTTP) POST request, in the same way that a web browser does. This will pass the data using the content-type application/x-www-form-urlencoded. Compare to -F, --form.
-d, --data is the same as --data-ascii. To post data in pure binary, use --data-binary.	To URL-encode the value of a form field you may use --data-urlencode. Multiple date options will be merged together. Thus, using '-d name=daniel -d skill=lousy' would generate a post that looks like 'name=daniel&skill=lousy'. If the data starts with @, the rest should be a filename containing the data.
-F name=@file -F name=content --form name=content	Emulate a filled-in form in which a user has pressed the submit button. This will POST data using the Content-Type multipart/form-data according to RFC 2388. This enables uploading of binary files etc. If the data starts with @, the rest should be a filename. To just get the content part from a file, prefix the file name with the symbol <. The difference between @ and < is that @ makes a file get attached in the post as a file upload, while the < makes a text field and gets the contents for that text field from a file.
-k --insecure	This option explicitly allows curl to perform "insecure" SSL connections and transfers. All SSL connections are attempted in secure mode using the CA certificate bundle installed by default. This makes all connections considered "insecure" fail unless -k, --insecure is used.(SSL).
--limit-rate speed	Specify the maximum transfer rate. This feature is useful if you have a limited pipe and you'd like your transfer not to use your entire bandwidth. The given speed is measured in bytes/second, unless a suffix is appended. Appending 'k' or 'K' will count the number as kilobytes/sec, 'm' or M' megabytes, while 'g' or 'G' makes it gigabytes/sec. Eg: 200K, 3m, 1G.
-m seconds --max-time seconds
-o file --output file	Write output to file instead of stdout. If you are using {} or [] to fetch multiple documents, you can use '#' followed by a number in the file specifier. That variable will be replaced with the current string for the URL being fetched. Like in: curl http://{one,two}.site.com -o "file_#1.txt" or use several variables like: curl http://{site,host}.host[1-5].com -o "#1_#2" You may use this option as many times as the number of URLs you have. See also --create-dirs option to create the local directories dynamically. Specify '-' to force the output to stdout.
-O --remote-name	Write output to a local file named like the remote file we get. (Only the file part of the remote file is used, the path is cut off.) The remote file name to use for saving is extracted from the given URL, nothing else. Consequentially, the file will be saved in the current working directory.
-s --silent	Silent or quiet mode. Don't show progress meter or error messages.
--trace-ascii file	Enable a full trace dump of all incoming and outgoing data, including descriptive information, to the given output file. Use "-" as filename to have the output sent to stdout. This option overrides previous uses of -v, --verbose or --trace-ascii. If this option is used several times, the last one will be used.
-T file --upload-file file	Transfer the specified local file to the remote URL. PUT If there is no file part in the specified URL, Curl will append the local file name. You must use a trailing / on the last directory to really prove to Curl that there is no file name or curl will think that the last directory name is the remote file name to use. Use the file name "-" to use stdin. You can specify one -T for each URL on the command line. Each -T + URL pair specifies what to upload and to where. curl also supports "globbing" of the -T argument, meaning that you can upload multiple files to a single URL like this: curl -T "{file1,file2}" http://www.uploadtothissite.com or even curl -T "img[1-1000].png" ftp://ftp.picturemania.com/upload/
-I --head	Fetch the HTTP-header only! (HTTP/FTP/FILE) HTTP-servers feature the command HEAD which this uses to get nothing but the header of a document. When used on an FTP or FILE file, curl displays the file size and last modification time only.
-u user:password --user user:password	The username and password to use for server authentication. Overrides -n, --netrc and --netrc-optional. If you just give the user name (without entering a colon) curl will prompt for a password. If you use an SSPI-enabled curl binary and do NTLM authentication, you can force curl to pick up the username and password from your environment by specifying a single colon with this option: "-u :". If this option is used several times, the last one will be used.
-w --write-out format	Define extra info to display on stdout after a completed and successful operation. The format is a string that may contain plain text mixed with any number of variables. The format string can be specified as "string", or to read from a file specify "@filename" to read the format from stdin use "@-". Various variables may be included in the format and will be substituted by curl (file size, ip address etc see man curl for details). variables are specified as %{variable_name} Output a newline using \n, a carriage return with \r and a tab space with \t.
-x host:port -x [protocol://][user:password@]proxyhost[:port] --proxy [protocol://][user:password@]proxyhost[:port]	Use the specified HTTP proxy. If the port number is not specified, it is assumed at port 1080.
-H "name: value" --header "name: value"	Add Header when getting a web page. You may specify any number of extra headers.
-H "name:" --header "name:"	Remove Header, remove an internal header.
-L --location	Follow redirects if the server reports that the requested page has moved (indicated with a Location: header and a 3XX response code)
-v --verbose	Make more verbose/talkative. Mostly useful for debugging.

EXAMPLES

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

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

To retrieve a web page and display in the terminal

$ curl http://www.tutorialspoint.com

To retrieve a web page and display header information

$ curl http://www.tutorialspoint.com -i

To retrieve a web page and save to a file.

$ curl http://www.tutorialspoint.com -0 tutorialspoint.html

To retrieve a web page, or its redirected target

$ curl www.tutorialspoint.com/unix/

$ curl www.tutorialspoint.com/unix/ --location

To limit the rate of data transfer to 1 Kilobytes/sec

$ curl http://www.tutorialspoint.com/unix/ --limit-rate 1k -o unix.html

To download via a proxy server

$ curl -x proxy.example.com:3128 http://www.tutorialspoint.com/unix/