Licenses and Copyright

If you program for Linux, you do need to understand licensing, no matter if you are writing free software or commercial software. Here's a road map.
Shareware Licensing

Shareware hasn't really caught on in the Linux world. Perhaps because so much quality software is available without any sort of payment, and perhaps because Linux grows out of the movement to write free software for Unix and predates the shareware movement, there are only a few popular shareware packages in the Linux world. Most of these provide for optional payment for personal use, and required payment only for business or commercial use. There are no legal restrictions that keep you from releasing shareware for Linux, but be aware that you are entering relatively uncharted waters if you choose to license a Linux application as shareware.

It's Not That Hard

The most important thing to remember is that licensing isn't a particularly complicated issue in most cases. This entire article has been concerned mostly with exceptional cases. Most normal application vendors and most free software authors will have no licensing issues to resolve. Just be aware of the differences between licensing techniques, so that you will be aware of the issues involved. if you ever do have a problem to resolve.

Michael K. Johnson ( is the outgoing editor of Linux Journal, and as a programmer has worked on both free and commercial software for Linux. He is now a programmer at Red Hat Software, creators and maintainers of the Red Hat Linux distribution.