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Manual Pages

Manual Pages is one stop help for the commands and utilities in Linux OS. To read the manual pages man command is used.

$ man uptime
$ man dmidecode

One line descriptions of manual pages can be displayed using whatis command.

$ whatis uptime
$ whatis dmidecode

Manual Pages database can be used to search for the short description of the command. It can also be used to search for the command if you don’t know the command itself by searching for keywords.

$ man -k copy
$ man -k authentication
$ apropos move

In order to create the Manual Pages database run commandmandb as root user.

# mandb

Manual Pages has 9 sections in which the manual pages are classified.

  1. Executable programs or shell commands
  2. System calls (functions provided by the kernel)
  3. Library calls (functions within program libraries)
  4. Special files (usually found in /dev)
  5. File formats and conventions eg /etc/passwd
  6. Games
  7. Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7)
  8. System administration commands (usually only for root)
  9. Kernel routines [Non-standard]

Non-standard sections are as given below.

  • 0
    Header files
  • 0p
    Header files (POSIX)
  • 1p
    Executable programs or shell commands (POSIX)
  • 3n
    Network Functions
  • 3p
    Perl Modules
  • l
    Local documentation
  • n
    New manpages

Sometimes we have the same command name and file name like in case of passwd. Sometimes we have the same name for command and library call like in case of printf. In such case, we have to mention section number to see the respective manual page entry.

$ man -f passwd
$ man passwd
$ man 5 passwd
$ man printf
$ man 3 printf

To read the history of Manual Pages click Here

INFORMATION PAGES

GNU Information Pages are also helpful to find about what the command does.

$ pinfo uptime

DOCUMENTATION IN /USR/SHARE/DOC

The documentation can be read using file reading commands or by using a text editor.