Enable Php Curl Extension Linux

i just want to know how i can enable Curl in my linux server please. not sure which mod i need if cURL and libcurl?

incase you guys dont know what im talking about here is the description:

libcurl

A free and easy-to-use client-side URL transfer library, supporting FTP, FTPS, HTTP, HTTPS, SCP, SFTP, TFTP, TELNET, DICT, FILE, LDAP and LDAPS. libcurl supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading, kerberos, HTTP form based upload, proxies, cookies, user+password authentication, file transfer resume, http proxy tunneling and more.

libcurl is portable, it builds and works identically on several platforms, including Solaris, NetBSD, FreeBSD, OpenBSD, Darwin, HPUX, IRIX, AIX, Tru64, Linux, UnixWare, HURD, Windows, Amiga, OS/2, BeOs, Mac OS X, Ultrix, QNX, OpenVMS, RISC OS, Novell NetWare, DOS and more...

libcurl is free, thread-safe, IPv6 compatible, feature rich, supported and fast. Software programmers may incorporate libcurl into their programs. Bindings in more than 40 languages are available for libcurl.

curl

A command line tool for getting or sending files using URL syntax.

Since curl uses libcurl, it supports a range of common Internet protocols, currently including HTTP, HTTPS, FTP, FTPS, SCP, SFTP, TFTP, LDAP, LDAPS, DICT, TELNET and FILE.

The name of the project is a play on 'Client for URLs', originally with URL spelled in uppercase to make it obvious it deals with URLs. The fact it can also be pronounced 'see URL' also helped, it works as an abbreviation for "Client URL Request Library" or why not the recursive version: "Curl URL Request Library".

Daniel Stenberg started writing cURL in 1997, as a way to transfer files via protocols such as http, ftp, gopher, and many more, via a command-line interface. Several other persons made important and crucial contributions to the project. Distributed under the MIT License, cURL is free software.