The UNIX on-line system is called man (short for manual). To get information about the ls command for example type:-
man lsNow press RETURN to step through the help line by line or press the space bar to step screen by screen. To quit before the end press q.
This only works if you know the name of the command. Many UNIX commands are not exactly intuitive (cat to type for example) and then you need to use the -k option. Typing:-
man -kxxx gives a list of all the subjects that have the keyword xxx as part of the title. If you did not know the cat command you could try:-
man typebut unfortunately that won't list cat. If you are persistent you will probably try:-
man -k printsooner or later which would list it.
The way man works is not very flexible; you are forced to read from start to end and cannot move back. To get round this, direct the output from man into a temporary file e.g.:-
man cat tempand then run the more command on this file:-
more tempThe more command allows you to display any part of the file. Once more is running just press ? to get a list of the commands. In fact you can press ? even when you run man directly but not all the commands work in this case and in particular those that move back through the file.
As you might expect, to get more information on man type:-