Use the man command to display the online manual pages of the grep command. How many versions of grep does your system support? Write down the names of these versions. How would you display a brief description of the built-in command set?

What will be an ideal response?

Our system supports three versions of the grep command: grep, egrep, and fgrep (see output of the man grep command below).
$ man grep
GREP(1) GREP(1)

NAME
grep, egrep, fgrep - print lines matching a pattern

SYNOPSIS
grep [options] PATTERN [FILE...]
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$
You can use the help set command to display a brief description of the built-in command set, as shown in the following session.
$ help set | more
set: set [--abefhkmnptuvxBCHP] [-o option] [arg ...]
-a Mark variables which are modified or created for export.
-b Notify of job termination immediately.
-e Exit immediately if a command exits with a non-zero status.
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$