What you probably don't know as a new Linux user is that a great deal of documentation is installed on your system when it is initially set up. On my system, which is running Fedora Core I, that documentation is stored in the directory /usr/share/doc. There you will find directories for most of the command on your system. In those directories you'll find extensive documentation in man page, html, and often other formats.
If you are using a Linux system that use RPM to manage your application packages, you can use the query documentation form of the rpm command, rpm -qd, to locate the documentation files for that package. See the figure below:
Figure 8. Example of Using RPM Documentation Query
[rben@Prot rben]$ rpm -qd XFree86 /usr/X11R6/man/man1/XFree86.1x.gz /usr/X11R6/man/man1/Xmark.1x.gz /usr/X11R6/man/man1/Xserver.1x.gz /usr/X11R6/man/man1/appres.1x.gz . . . /usr/X11R6/man/man7/X.Org.7x.gz /usr/X11R6/man/man7/XConsortium.7x.gz /usr/X11R6/man/man7/XProjectTeam.7x.gz /usr/X11R6/man/man7/XStandards.7x.gz /usr/X11R6/man/man7/Xsecurity.7x.gz /usr/share/doc/XFree86-4.3.0/CHANGELOG [rben@Prot rben]$
If you try the example above, you'll see that I left out most of the resulting listing of files. Each of the files that you find in the /usr/.../man/man1/ directories is actually a man page that can be viewed by typing man filename where filename is the filename without the .something.gz extension. For instance in the example above, I can see that I can use the command man Xsecurity to learn more about security for the X Windows system.