Help how to open UNX files:
It can be opened by a standard text editor on Unix, Windows, and Macintosh computers.
How to convert file with extension UNX:
If your opened file type is simple text file, you don't need to converting it. You can rename file extension to .txt or text file extension you currently need for your associated program or project. There can be sometimes problems with right character encoding recognition and determining of used charset for text in the file and consequently converting into character set you want. Look for some text encoding converter software if your text editor can't convert text into code charset you need.
If your file is not simple text file (viewed text is corrupted, contains unknown symbols, special characters or binary code), you will need to find native text editor or word processing program for this file type or similar program capable to import this text file format. Try to do some internet search for the right application for this file type.