I\'m using grep to match string in a file. Here is an example file:
example one, example two null, example three, example four null,
grep
Refer this link for linux command linux http://linuxcommand.org/man_pages/grep1.html
for displaying line no ,line of code and file use this command in your terminal or cmd, GitBash(Powered by terminal)
grep -irn "YourStringToBeSearch"