[zeitalex]

how to edit large set of *.nfo files. I would like for example to replace language of audio stream with unique name. replace English, en, etc., with eng. *.nfo files are located in different folders.

[tars]

That's an easy task for Notepad++: http://cybernetnews.com/find-replace-multiple-files/

But keep in mind those changes will be overwritten whenever you rescrape movies or rebuild NFO files.