Common grep usage

Common grep usage
Grep Introduction

As described in the linux man file:

Grep searches the named input FILEs (or standard input if no files are named, or if a single hyphen-minus (-) is given as file name) for lines containing a match to the given PATTERN. by default, grep prints the matching lines. in addition, two variant programs egrep and fgrep are available. egrep is the same as grep-E. fgrep is the same as grep-F. direct invocation as either egrep or fgrep is deprecated, but is provided to allow historical applications that rely on them to run unmodified.

Grep is a command used to search for lines that match the given pattern in a file. Both egrep and fgrep have been discarded and replaced by grep-E and grep-F.

How to search for rows containing strings in a single file

Syntax:
Grep "literal_string" filename

Search for rows containing strings in multiple files

Syntax:
Grep "this" demo _*
Note: The Search domain is a file prefixed with demo _.

Use the-I parameter to implement case-insensitive filtering using regular expressions.

Syntax:
Grep "REGEX" filename