Learning Linux Shell Scripting

Pattern searching using grep

The g/RE/p stands for globally search for the regular expression (RE) and print out the line.

Return status – success 0, pattern not found 1, file not found 2.

$  ps -ef | grep root

The preceding command will show all processes running currently whose user ID is "root".

$  ll /proc | grep "cpuinfo"

The preceding command will show the file with the name cpuinfo from the /proc directory.

$  grep –lir "text" *   // only file names  //   
$ grep –ir  "text" dir_name   // show lines of files //

We will try the following commands on the love.txt file:

Metacharacter	Function	Example	Description
^	Beginning-of-line anchor	'^mango'	Will display all lines beginning with mango
$	End-of-line anchor	'mango'$'	Will display ...