Search for File Contents in Nautilus

Create a script file (text file) called "Find" in "~/.gnome2/nautilus-scripts" and allow it to be executable. Add the commands below in the script file:- 

#!/bin/bash
gnome-search-tool --hidden --path="$*" --contains= 

From its command help:-
--hidden               Select the "Show hidden and backup files" search option
--path=PATH            Set the text of "Look in folder" search option
--contains=STRING      Select and set the "Contains the text" search option

To search for files using this script in Nautilus,

Right click a folder -> Scripts -> Find

Refs
http://forums.linuxmint.com/viewtopic.php?f=42&t=25114