man

man is the command for manual pages. See the usage a command by running man <cmd> in the terminal.

There are also cheat sheets with a brief example for a command.

cheat.sh

cheat.sh is an online cheat sheet that can be also accessed via the curl command.

For example,

curl cht.sh/tar

tldr

tldr are collaborative cheat sheets for console commands, a complement to man pages.

Go to tldr’s InBrowser.App in a web browser.

tealdeer

tealdeer is a fast implementation of tldr in Rust. tldr are simplified, example based and community-driven man pages.