4. Manual Pages

Before we discuss some common commands, you might want to get more information than is presented in this tutorial such as proper usage, and additional arguments that a command might take. Linux includes a built in manual for nearly all commands. The syntax for accessing these manuals is to use the man command followed by the program name. "man" formats and displays the on-line manual pages. If you specify a section, "man" only displays that section of the manual.

To navigate the man pages use the arrow keys to scroll up and down or use the enter key to advance a line and the space bar to advance a page. Use the q key to quit out of the display.

The manual pages follow a common layout. Sections may include the following topics:

1. Name--a one line description of what it does.
2. Synopsis--basic syntax for the command line.
3. Description--describes the program's functionalities.
4. Options--lists command line options that are available for this program.
5. Examples--examples of some of the options available
6. See Also--list of related commands.

Example: rm(Remove).

$ man rm
RM(1)                            User Commands                           RM(1)
    
NAME
    rm - remove files or directories
    
SYNOPSIS
    rm [OPTION]... FILE...
    
DESCRIPTION
    This  manual page documents the GNU version of rm.  rm removes each 
    specified file. By default, it does not remove directories.

     If the -I or --interactive=once option is given,  and  there  are  more
     than  three  files  or  the  -r,  -R, or --recursive are given, then rm
     prompts the user for whether to proceed with the entire operation.   If
     the response is not affirmative, the entire command is aborted.

     Otherwise,  if  a file is unwritable, standard input is a terminal, and
     the -f or --force  option  is  not  given,  or  the  -i  or  --interac-
     tive=always  option is given, rm prompts the user for whether to remove
     the file.  If the response is not affirmative, the file is skipped.

The first 3 sections of the "rm" command provides basic information and functionality. The NAME section describes what "rm" can do. The SYNOPSIS section gives the basic syntax of the command. The DESCRIPTION section elaborates on the functionality of the command. For example, "rm" does not remove directories without the -r option; it won't remove unwritable files without appending the -f option.

Depending on the command, the OPTIONS section can be quite lengthy

OPTIONS
    Remove (unlink) the FILE(s).

       -f, --force
              ignore nonexistent files, never prompt

       -i     prompt before every removal

       -r, -R, --recursive
              remove directories and their contents recursively

       -v, --verbose
              explain what is being done