Η application Office Search will help you find text from within Microsoft Office, RTF files and in general from all text files.
You can search Microsoft Office (Word, Excel, Power Point), LibreOffice (Writer, Calc, Impress), Visio, RTF and ASCII text files (TXT / CSV / MD / HTML / PHP, etc.) .
For all other files it will use fuzzy logic to check if the file is text or binary. If you don't remember it name of the file, give a part of the text present in the content, and it will display the contents of the matching files. The application runs on Windows 7/8 and 10.
Even if your folders are not meticulously arranged, you can easily find your documents as long as you remember a little of what they say.
If you know that certain file types are ASCII, you can add these file types to the config file so that you can search the application.
It supports characters Unicode/non-English, so you can use the app for Greek text as well.