tldr pages - Collaborative cheatsheets for console commands
https://github.com/tldr-pages/tldr

The tldr-pages project is a collection of community-maintained help pages for command-line tools, that aims to be a simpler, more approachable complement to traditional man pages.
Maybe you're new to the command-line world? Perhaps you're just a little rusty or can't always recall the arguments for commands like `lsof`, or `tar`?
It certainly doesn't help that, in the past, the first option explained in `man tar` was: