Other good bash info: https://devhints.io/bash
Another cool link: https://dev.to/awwsmm/101-bash-commands-and-tips-for-beginners-to-experts-30je
Another one: https://github.com/trimstray/the-book-of-secret-knowledge#tool-terminal
Given a command, shows you the location of the file executed when the command is called
$ which grep
/bin/grep
like a more verbose which
$ whereis grep
grep: /bin/grep /usr/share/man/man1/grep.1.gz /usr/share/info/grep.info.gz
a short description of the command. Like a short man page.
$ whatis grep
grep (1) - print lines matching a pattern
Use to find out the type of a command. Link
TODO: Add extra info here
Lists possible "completion options". I just use it to see what commands I can run.