cURLis a computer software project providing a library and command-line tool for transferring data using various protocols. The name originally stood for "see URL" - wikipedia 
- curl POST examples here - mkyong.com
# cURL
Since cURL uses libcurl, it supports a range of common Internet protocols, currently including HTTP, HTTPS, FTP, FTPS, SCP, SFTP, TFTP, LDAP, DAP, DICT, TELNET, FILE, IMAP, POP3, SMTP and RTSP (the last four only in versions newer than 7.20.0 or 9 February 2010).
cURL supports HTTPS and performs SSL certificate verification by default when a secure protocol is specified such as HTTPS.
Basic use of cURL involves simply typing curl at the command line, followed by the URL of the output to retrieve - wikipedia
To retrieve the example.com homepage, type:
curl www.example.com
cURL defaults to displaying the output it retrieves to the standard output specified on the system (usually the terminal window). So running the command above would, on most systems, display the www.example.com source-code in the terminal window.
cURL can write the output it retrieves to a file with the -o flag, thus:
curl -o example.html www.example.com
This will store the source code for www.example.com into a file named example.html. While retrieving output, cURL will display a progress bar showing how much of the output has downloaded. Note however that cURL does not show a progress bar when preparing to display the output in the terminal window, since a progress bar is likely to interfere with the display of the output.
To download output to a file that has the same name as on the system it originates from, use the -O flag, for example:
curl -O www.example.com/example.html
If the server responds that the file (example.html) is moved to a different location (indicated with a Location: header and a 3XX response code), use the -L flag, for example:
curl -OL www.example.com/example.html
cURL can connect to a remote server via HTTPS protocol (return error message if a CA certificate file cannot be located)
curl https://securesite.com/login.html
To specify a CA certificate file:
curl --cacert c:\temp\cacerts.crt https://securesite.com/login.html
To skip certificate verification:
curl --insecure https://self-signed-cert.com/login.html
Curl offers many other features such as proxy support, user authentication, FTP upload, HTTP post, SSL connections, cookies, file transfer resume, Metalink, as well as various other features.
# See also