As you read through this book, you will want to get more information about the commands and features that are discussed. Much of this information is available by using the online help features of UNIX. Some other resources include Web sites that cover shell programming and Usenet newsgroups.
Every version of UNIX comes with an extensive collection of online help pages called man pages (short for manual pages). The man pages are the authoritative source about your UNIX system. They contain complete information about both the kernel and all the utilities.
You can access man pages by using the man command:
Here, cmd is the name of a command that you want more information about. As an example,
$ man uptime
displays the ...