grep stands for Globally Search For Regular Expression and Print out. It is a command line tool used in UNIX and Linux systems to search a specified pattern in a file or group of files.

grep comes with a lot of options which allow us to perform various search-related actions on files. In this article, we’ll look at how to use grep with the options available as well as basic regular expressions to search files.

**How to use ****grep**

Without passing any option, grep can be used to search for a pattern in a file or group of files. The syntax is:

grep '<text-to-be-searched>' <file/files>

Note that single or double quotes are required around the text if it is more than one word.

You can also use the wildcard (*) to select all files in a directory.

The result of this is the occurences of the pattern (by the line it is found) in the file(s). If there is no match, no output will be printed to the terminal.

For example, say we have the following files (called grep.txt):

Hello, how are you
I am grep
Nice to meet you

The following grep command will search for all occurences of the word ‘you’:

grep you grep.txt

The result for this is:

Hello, how are you
Nice to meet you

you is expected to have a different color than the other text to easily identify what was searched for.

But grep comes with more options which help us achieve more during a search operation. Let’s look at nine of them while applying them to the example above.

#linux