Understanding Linux man Pages



Understanding Linux Manual (man) Pages


Man pages are the work of various people doing their best to describe the commands and their usage. Man pages come from different sources and most are similar but not all. Manual pages were generally written by the persons who wrote the program themselves. They are descriptive enough but it's not a full documentation. Man pages themselves are broken up into several parts, indicated and organized by heading terms. Most heading terms you will see in man pages are common across different man pages, and will be presented in the same order in each case.

Man pages are the most reliable command for getting help. Man pages are not easy to understand in starting, but when you start reading man pages you will get familiar with it. If you are in doubt how the commands work you can just simply type man command. For getting help how to read man pages you can also type command man man for man page help.





Man Page Linux


Different headings in man pages

For man pages of ls

$ man ls

LS(1)                                        User Commands                                                                 LS(1)


NAME


       ls - list directory contents


SYNOPSIS


       ls [OPTION]... [FILE]...


DESCRIPTION


       List information about the FILEs (the current directory by

       default).  Sort entries alphabetically if none of -cftuSUX

       nor --sort.


       -a, --all

              do not hide entries starting with .


       -A, --almost-all

              do not list implied . and ..


       -b, --escape

              print octal escapes for nongraphic characters


       --block-size=SIZE

              use SIZE-byte blocks


       -B, --ignore-backups

              do not list implied entries ending with ~


       -c     with  -lt:  sort  by, and show, ctime (time of last

              modification of file status information)


              with -l: show ctime and  sort  by  name  otherwise:

              sort by ctime

                                ----

                                ----

                                ----

                                ----

-X     sort alphabetically by entry extension

        -1     list one file per line
        --help display this help and exit
        --version
              output version information and exit

 
       By default, color is not  used  to  distinguish  types  of

       files.   That  is equivalent to using --color=none.  Using

       the --color option without the optional WHEN  argument  is

       equivalent  to  using  --color=always.  With --color=auto,

       color codes are output only if  standard  output  is  con­

       nected to a terminal (tty).

 
AUTHOR

 
       Written by Richard Stallman and David MacKenzie.

 
REPORTING BUGS

 
       Report bugs to <bug-fileutils@gnu.org>.

 
COPYRIGHT

 
       Copyright © 1999 Free Software Foundation, Inc. 
       This  is  free software; see the source for copying conditions. 
       There is NO warranty; not even for MERCHANTABILITY or 
       FITNESS FOR A PARTICULAR PURPOSE.
 
SEE ALSO

 
       The  full  documentation for ls is maintained as a Texinfo manual. 
       If the info and ls programs  are   properly installed at your site, the 
       command info ls should give you access to the complete manual.



The different headings are described below

ls (1) 

It shows the command that you search. 1 indicates the section you have searched.  Man pages have different sections.

Man page sections are:

     (1)     User Commands
     (2)     System Calls
     (3)     Library functions
     (4)     Devices
     (5)     File formats
     (6)     Games and Amusements
     (7)     Conventions and Miscellany
     (8)     System Administration and Priveledged Commands
     (L)     Local. Some programs install their man pages into this section instead of (1)
     (N)     TCL commands

For different sections man pages you can use the command

$ man k ls
Or
$ man –k ls
Where k is the section as described above.


NAME

The name of the command and a brief description.

SYNOPSIS

This describes the various flags and the proper format the command require.  The synopsis is shown using the command followed by [OPTION]... [FILE]...

The "OPTIONS" in Brackets “[ ]” indicates that this is not necessary, but it can be used.

It is followed by a "..." means this can be used one or more times.

So now let’s analyze the above synopsys

ls [OPTION]... [FILE]...

Here ls command after that option in bracket then … then file in bracket then …
Means option and file are not necessary but can be used and many option and file can be there

Here are some examples

 ls           
no option no file only ls can be used it list all files in the present directory

ls –l
One option but no file. It lists the files in present directory in detail description of files.

ls -l /home
One option and one file. It lists the detail of files in home directory.

ls -al /home  or ls -a-l /home

Here two options and one file.
It is the detail description of the Synopsis heading. If you understand it then you get almost all about using the command.

DESCRIPTION  

A detailed description of what the command will do. It highlights specific functions of the command mentioned and also provides the OPTIONs available for the command.

OPTIONs are preceded by hyphens.
You can either specify them individually with a space in between them as (ls -a -l)
It can also be used together as ( ls -al).
You can use -a or --all as ls -a or ls --all both gives same result

AUTHORS

The people who has created and assisted in the creation of the command.

REPORTING BUGS

If you find any problems with the command, this tells you where you should report the defects or problems you are having with the command.

COPYRIGHT

The person or organization that holds the copyright to this information.

SEE ALSO



Other commands that are related to this command.



File Types in Linux                                Keyboard ctrl commands in Linux

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