
command --help and man command are the two most important tools at the command line.
Virtually all commands understand the -h (or --help) option, which will produce a short usage description of the command and its options, then exit back to the command prompt. Type:
man -h
or
man --help
to see this in action.
Every command and nearly every application in Linux™ has a man (manual) file. It is as simple as typing man command to bring up a longer manual entry for the specified command. For example:
man mv
brings up the mv manual.
Move up and down the man file with the arrow keys, and quit back to the command prompt with q.
man man
brings up the manual entry for the man command, which is a good place to start.
man intro
is especially useful. It displays the “introduction to user commands” which is a well-written, brief introduction to the Linux™ command line.
There are also info pages, which generally go into more detail than man pages. Try:
info info
for the introduction to info pages.
If you aren't sure which command or application you need to use, you can search the man files.
To search the man files for konsole, try:
man -k konsole
Note
This is the same as the apropos command.
To search only the titles of your system's man files, try:
man -f kde
Note
This is the same as the whatis command.