CURL or Client URL Library is command line tool which is used to transfer data from one server to another. Basically, the tool is designed to help you get or send files using URL based syntax and it works without user interaction.
CURL supports wide variety of common Internet protocols including HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMTP, SMTPS, TELNET, TFTP, DICT, FILE, FTP, FTPS, GOPHER etc.
CURL = Client URL Library
In other words, CURL is a browser for scripting languages (such as PHP) or server functions. Those who are familiar with the *NIX application LYNX may be right at home with CURL’s features.