UNIX & GNU/Linux - User commands - Using grep

Maybe you sometimes asked yourself how to find a part of a code inside all your files.
But how to find this part of code?
We can use the grep user command to display this part of a code.

We can moreover display this code in color.

Let's see an example of the grep user command.

The line below has to be typed directly in your favourite shell:

$ grep --color main *

The result is the code "main" in red and the file where the code is found (in purple).

Really helpfull isn't it?