GREP is a command line search utility or tool to filter the input given to it. Grep got its name from ed editor as g/re/p (global / regular expression / print). Grep command can improve a command output by filtering out the required information. Grep will become a killer command when we combined it with regular expressions. In this post, we will see how to use grep command in a basic way and then move on some advanced and rarely used options. In our next couple of posts, we will see what grep can do with the help of regular expressions.