Learning Linux Shell Scripting - Second Edition

Pattern searching using grep

The command g/RE/p stands for globally search for the regular expression (RE) and print the line. The return statuses are 0 for success, 1 for pattern not found, and 2 for file not found:

    $ 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" *          // show only file names containing text //   
    $ grep -ir "text" dir_name    // show lines of files //

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

Meta-character	Function	Example	Description
^	Beginning-of-line anchor	'^mango'	Will display all lines beginning with mango