Thursday, July 24, 2014

Customizing the UNIX User Environment - Part 4 - UNIX documentation - Part 2

Customizing the UNIX User Environment


UNIX documentation


Navigation Options


Let's say you want to find out what the ps command does. To invoke the ps man page (also called manual page), at the shell prompt, you type

man ps (hit enter)


The man page opes, giving a description of the command. In this case, you see that the ps command is used to list the status of processes


Manual (man page) description for ps starts like the following



PS(1)                     FreeBSD General Commands Manual




                ps - process statis


                ps [-aCcefhjlmrSTuvwx] [-M core] [-N.......



the 1 in PS(1) indicates that this belongs to the first of the eight sections of the manuals


Man pages generally contain more information than can fit on one screen , so a pager displays the pages for navigation purposes


Usually, man pages are fusplayed using the pager specified in the $PAGER environment variable.


If you dont want to use your environment;s default pager, you can specify a pager with the -p option. For example, the command man -P less ps changes the pager environment from the default ps pager evironment, which you navigate by using keystrokes to a pager environment where you can execute search commands.


On Most systems, you can use the following key to navigate man pages:


- space and b

  space - allows user to move one page down from a current man page

  b - one page up from current man page

- down or j and up or k arrows - allows users to move one line down or up in man page

- G and g - allows users to move to end and start of document respectively

- q - allows users to exit a current man page environment


Headings of a typical man page format


-NAME  - you will find the name of the command or program and a short description of it

-SYNOPSIS  - you will find a description of the synatax

-DESCRIPTION  - provides explanation of the command or utility

-OPTIONS  - provides explanation of command -line options

-ENVIRONMENT - you will find definitions of relecant environment variables

-EXAMPLES - will have usages and short explanation of the commands

-SEE ALSO - provides reference to other relevant man pages

-FILES - the FILES heading is found in the man pages of programs that use configuration files. The heading contains information on the location and function of these configuration files


Different man pages may have different formats. As a result, some man pages may have only some of the typical headings discussed here.

For example, there are no configuration files for the cat command, so that heading is not on the man page.


The format of a man page includes sections to indicate an exiting program, returning program and errors.

It also includes section for listing the system files that a command uses and for linking the user to related man pages.

The format of a man page may also include a section for notes and bugs related to a command.

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