Main sources for info and all parts of the operating system are:

• man - man
• info - info
• apropos
• whatis
• help (for Bash Builtins)
• Package documentation at /usr/share/docs/<package>

<command> --help

Another important source of Linux documentation is use of the –help option.

Most commands have an available short description which can be viewed using the –help or the -h option along with the command or application. For example, to learn more about the man command, you can run the following command:

man --help

The –help option is useful as a quick reference and it displays information faster than the man or info pages.

Some popular commands (such as echo), when run in a bash command shell, silently run their own built-in versions of system programs or utilities, because it is more efficient to do so. To view a synopsis of these built-in commands, you can simply type help.

For these built-in commands, help performs the same basic function as the -h and –help arguments (which we will discuss shortly) perform for stand-alone programs.

There are many places to access online Linux documentation, and a little bit of searching will get you buried in it. The following site has been well reviewed by other users of this course and offers a free, downloadable command line compendium under a Creative Commons license:

• LinuxCommand.org: http://linuxcommand.org/tlcl.php

You can also find very helpful documentation for each distribution. Each distribution has its own user-generated forums and wiki sections. Here are just a few links to such sources:

• Ubuntu: https://help.ubuntu.com/
• CentOS: https://www.centos.org/docs/
• OpenSUSE: http://en.opensuse.org/Portal:Documentation
• GENTOO: http://www.gentoo.org/doc/en

Moreover, you can use online search sites to locate helpful resources from all over the Internet, including blog posts, forum and mailing list posts, news articles, and so on.

~~DISCUSSION~~