Now that you are familiar with the built-in help in Unix and how to use the man pages and the man command, we will look at some other ways to use man. We'll also explore the use of apropos and whatis, two programs that can help you find additional assistance.
As mentioned earlier, the man command can often generate unwieldy results. This can be especially problematic if you just want to see a subset of the information on a man page. If this subset is all you need (for example, if you only want to view a summary description of a command), then you can use the following commands:
whatis man –f apropos man –k
Using any of these followed by the command you are interested in (just like the man ls example) will result in a shorter set of ...