Grep's default behavior is to be case sensitive, however it is not always the case that you need to match the exact case if your search string. Good thing there is a built in command line switch to make grep ignore case.

Syntax

$ grep -i <searchstring> myfile.txt

Example

In this example lets assume my file has the following contents

$ cat myfile.txt
This is my file
I dont have a lot of data in this FILE
It is only for demonstration
$

And if I run the command above and search for "file" we will see the following output.

$ grep -i file myfile.txt
This is my file
I dont have a lot of data in this FILE
$

As you can see it pulls in the first to 2 lines even though the word "file" is in different case.