This is something you need to do often for one reason or another. Maybe you have a bunch of text files, which have been named horribly and you have no idea which file has the thing you are looking for, but you happen to remember a word in that file. Or maybe you need to find which file contains a certain variable to find the root cause of an error you are experiencing in your script.
What ever the reason may be, this command lets you search a directory recursively (meaning all the directories in it as well) to find your file(s). Below is the command.
grep -rnw '/give/your/path/' -e "pattern"
The command-line options are as the following: -r, Recursive -n, Gives you the line number -w, Searches the whole word -e, Searches the pattern you tell it.
Source: http://stackoverflow.com/questions/16956810/how-to-find-all-files-containing-specific-text-on-linux