Getting Help

Linux distributions include documentation about nearly all the programs, commands and files installed on your hard drive. each distributions also comes with a number of commands and programs to help you learn about the systems. Some of the commands will be discussed shortly.

Man

man command is used to display the manual pages of a command, file or other Linux function (actually the manual pages are displayed using a program called less). To read a manual page of a program or command just pass the program name as the argument of the man command. The following example will show you the manual pages of the cat program

man cat

The Manual pages are located in the /usr/man directory

Whatis

Use the whatis command if you're unsure about what a program does. The whatis command will give you a short synopsis about the specified program. For example, if you issue the command whatis cal, it will return the following result

cal (1)         - dispays a calendar and the date of easter 

The synopsis is extracted from the command's manual page and is stored in a database called whatis. The database is located under the /usr/man directory and is built each day by a crontab script run each week by the makewhatis.cron script int /etc/cron.weekly directory (this script runs the makewhatis program that is found under /usr/sbin directory).

apropos

apropos command uses the whatis database to display all related mathes of the command's name. Use apropos to find related command or actions for programs installed on your system. For example, issuing the command apropos bell returns the following result (the output may be different from yours, it depends on the distribution you use)

                   beep, flash (3)            - Curses bell and screen flash routines

                       bell (n)                        - Rings a display's bell