One of the many useful abilities of Notepad++, is to search multiple text files for a text string and find in files and folders - including subfolder and windows hidden files and folders - and even to find and replace in notepad this search text in all files.
Enter your folder and search options. On top of the standard Notepad++ search options, you might want to check the In all sub-folders and / or In hidden folders options, to make sure the search is done on all subfolder and also hidden file folder.
Click on Find All once you have set up your search criteria.
You will be returned the list files and directories containing result : how many results in how many files, and, for each file matching your search criteria, the file location, and the line number of each result.