Find out what a command doesAt the command line, run:
This will give you a one-line summary of a command.
If whatis doesn't work, the whatis database may not be built yet. To build the whatis database, enter this:
The apropos command searches a database of commands, using keywords:
I can't remember the name of the command I need
Note that your keyword might not work. So try different keywords until it does!
If apropos does not work, you probably need to rebuild the whatis database with this command: