“egrep” stands for “Extended Global Regular Expression Print”. It is a pattern searching command which is similar to grep command in linux. egrep renders the lines that match the pattern as an expanded regular expression. It reads a file line by line, looking for the search string or regular expression and printing out those lines that contain it.

Command

$ egrep [options] pattern [file]

Options

Here are details about some options.

Option	Details
-i	Ignore case differences in patterns and input data so that characters that only differ in case will match.
-f	Obtain patterns from File, one per line.
-e Pattern	Tells you about a pattern. It works like a simple pattern, but it is useful when the pattern starts with a minus sign (-).
-h	Display the matched lines, but do not display the filenames.
-c	Print out the number of matching lines in each file.
-l	Only shows a list of filenames.
-n	Show the lines that match and their line numbers.
-v	This makes all the lines that do not fit the pattern print out.
-w	Select  only  those  lines  containing  matches  that form whole words.
-x	Displays lines that exactly match the pattern without any extra characters.
-R	Read  all  files  under each directory, recursively.

Examples

• Now, let us see some examples.

egrep -i linux linux_introduction.txt

egrep -c Linux linux_introduction.txt

egrep -w Linux linux_introduction.txt

egrep -n Linux linux_introduction.txt

egrep -l Linux *

egrep -x Ubuntu linux_distributions.txt