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Linux Help

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.

command information database description
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 /usr/sbin/makewhatis. 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).