curl usage

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 [email protected] --form press=OK [URL]

referer

curl --referer http://www.referer.com http://www.destination.com

user agent

curl --user-agent "[User Agent]" [URL]

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