In Linux, there are various programs which provide help with Linux and Linux commands. With how many options there are, it can be difficult to decide which program to use. Here’s a quick cheat sheet to make that decision a bit easier.
|man||man pages||manual pages for commands, directories, systems|
|info||info nodes||man pages but more verbose and instructional|
|-h, –help||the command||command option that displays syntax and options|
|help||help||for commands built-in to the Linux shell|
|whatis||whatis database||one-line description of a given command|
|apropos||whatis database||whatis but allows partial command matches|
Man pages are included when installing software.
The whatis database is built from man pages. To initially build the database, run
If the man pages are updated, the whatis database won’t automatically update. To update
the database, run
makewhatis -u (or
whatisupdate on some systems).