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curl

A command-line tool and library for transferring data with URLs.

curl speaks dozens of protocols (HTTP, HTTPS, HTTP/2, HTTP/3, FTP, FTPS, SFTP, SCP, SMTP, IMAP, POP3, LDAP, MQTT, WebSocket, TFTP, Telnet, Gopher, and more) from the command line. The libcurl library it ships with provides the same capabilities to applications in almost every programming language, and is used by many major systems for HTTP and other transfers.

Daniel Stenberg started the project in 1996 (originally as httpget) and continues to lead its development today. curl is preinstalled on almost every Linux distribution, ships in macOS and Windows, and is one of the most widely deployed pieces of software on the planet — embedded in everything from cars and game consoles to smart appliances and medical devices.

The protocol breadth and the project's commitment to backward compatibility (URLs that worked twenty years ago still work today, with the same flags) have made curl the canonical "fetch this URL" tool. The cURL licence (a small permissive licence) keeps it freely usable everywhere, and the project is funded through corporate sponsorships and Stenberg's own consulting work via wolfSSL.

Debian/Ubuntu: sudo apt install curl
Fedora/RHEL:   sudo dnf install curl
Arch:          sudo pacman -S curl
macOS:         preinstalled (or brew install curl for the latest)