That is a big question! As well, there are many articles on line debating. If you Goggle Linux vs Unix you will find many of them.
- Linux is free and built by the open source community with many similarities to Unix
- Most software that runs on Unix can be re-compiled to run on Linux
- More software development and support, as of the last few years, has gone into Linux. Companies like IBM and Novell making huge investments.
- For almost any platform there is a port where Linux will run on it; Unix is much more limited.
- There are more on-line resources for Linux than Unix, only due to the popularity of Linux.
--- Eric ---