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The command that are used to get the help are discussed as :

1. Whatis

Display a short description of command , it uses a database that is updated nightly. Often not available immediately after installation.

Syntax:

# Whatis cal

2. Help

Display usage summary and argument list

Syntax:

--help

Example:

#Date –help

3. Man and Info:

Both provide documentation for command. Almost every command has a “man” page. Collection of pages are called linux manual.

# man date

# info date

Viewing Text Page

Syntax:

#less [option] [filename]

Example:

# less abc.txt

scroll with arrows/PgUp /PgDown

/text : search for text

n : Next Match

Option:

-c : Clear before displaying

-s : Squeeze multiple blank lines into a single blank line

Simply we can also use “less” along with pipe | as

# ll |less