massive txt find & replace using unique strings

Hallo everyone.
I have a folder consisting of several text files. Every file consists of a string, that can be easily found with regex. This string must be replaced with new text, that is unique to each file.
I prepared a csv file with 3 columns:
1 column: path & file name
2 column: string I'm looking for (old string); it can be defined either by an exact match or by regex (doesn't matter from my point of view)
3 column: new string, it will be replacing the old text; it consists of regex (e.g. line break, backreferences)

Do you know about any tool (I prefer Windows, but Linux is also aceptable) that can do this kind of job (must be a freeware app)?
Thanks in advance for all your help. Regards,
gordom

 

I have in the past used XVI32 for such tasks.