Useful search commands in GNU/Linux

Finding commands and stuff in Linux:

which <command>
Lists the first occurrence of the <command>

whereis <command>
Lists all occurrences of <command>

locate <command>
Lists all that contains the word

apropos <command>
Search man page descriptions for <*command*>

whatis <command>
Search man pages description for <command>

(sudo) find / -name <command>
Searches entire filesystem for <command>

Debian / Ubuntu based distros specific:

apt-cache search <command>
Lists packages containing <command> from package repositories

dpkg-query -S <command>
Searches the list of installed packages for <command>

dpkg -L <command>
Lists all files installed by <package>

FYI only 😉