README
curl is a command-line tool for transferring data from or to a server using URLs. It supports these protocols: DICT, FILE, FTP, FTPS, GOPHER, GOPHERS, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, MQTT, MQTTS, POP3, POP3S, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET, TFTP, WS and WSS.
Learn how to use curl by reading the man page or everything curl.
Find out how to install curl by reading the INSTALL document.
libcurl is the library curl is using to do its job. It is readily available to be used by your software. Read the libcurl man page to learn how.
Open Source
curl is Open Source and is distributed under an MIT-like license.