Introduction
curl is a tool to transfer data from or to a server, using one of the supported protocols (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET and TFTP).
The command is designed to work without user interaction.
curl offers a busload of useful tricks like proxy support, user authentication, FTP upload, HTTP post, SSL connections, cookies, file transfer resume, Metalink, and more. As you will see below, the number of features will make your head spin!
This is a simple summary about the usage of curl, for more details, just man curl in your terminal.
get raw content
curl www.sina.com
curl https://api.github.com/search/repositories?q=react
use -o option to write to file instead of stdout.
curl -o <filename> www.sina.com
follow redirect
use -L option to follow the redirect.
curl -L www.sina.com
# will go to www.sina.com.cn
show response header
use -i option to show the response header with response. use -I option to only display the response header.
curl -i www.sina.com
verbose
use -v option to make the operation more talkative.
curl -v www.sina.com
use --trace <filename> or --trace-ascii <filename> to write a debug trace to file.
curl --trace log.txt www.sina.com
curl --trace-ascii log.txt www.sina.com
send form data
simply add in the url for get method.
curl example.com/form.cgi?data=xxx
use -X option to specify request command. use --data option for post method.
curl -X POST --data "data=xxx" example.com/form.cgi
use --form option to specify httmp multipart data.
assuming the form was like below:
<form method="POST" enctype='multipart/form-data' action="upload.cgi">
<input type=file name=upload>
<input type=submit name=press value="OK">
</form>
curl --form upload=@localfilename --form press=OK [URL]
referer
curl --referer http://www.referer.com http://www.destination.com
user agent
curl --user-agent "[User Agent]" [URL]
cookie
use -b or --cookie option to read cookies from file or string.
curl --cookie "name=xxx" www.example.com
use -c option to write cookies to file after operation.
$ curl -c cookies http://example.com
$ curl -b cookies http://example.com
add header
curl --header "Content-Type:application/json" http://example.com
authentication
curl --user name:password example.com