i) man pages – These are manual pages .
- It contains interface to online reference manuals
- Press q to exit.
- How to Use ( Command ) – man command_name
- for all man pages of BASH shell, use
man bash
- It generally contains following information about command(command_name) :-
* Name
* Synopsis (Prototype)
* Description (Options)
* Author (author of command)
* Reporting Bugs (Feedback emails/Website)
* Copyright (copyright details)
* See Also (for further reference of command)

ii) Info pages – Read info documents
- It contains BASH manuals.
- Press q to exit
- How to Use (command) – info command_name
- It contains information about :-
* Prototype
* Introduction
* Options
* Exit Status
iii) help command
- It gives basic help for using a command and its various options.
- It gives output on Standard Output.
- It do not require exit command.
- How to Use (command) – help command_name
- It contains following information about command (command_name) :-
* Function of command
* Options
* Exit status

eg.
man echo
info echo
help echo

- To check total no. of enteries in each of three
I) type either of three (with space at end)
II) Press tab button for 3-4 times.
We will get the total number of possible options defined or list of them also.
eg. (<tab> means Press tab button)
man <tab><tab><tab>