A free program allows you to tinker with it to make it do what you want (or cease to do something you dislike). Tinkering with software may sound ridiculous if you are accustomed to proprietary software as a sealed box, but in the Free World it's a common thing to do, and a good way to learn programming. Even the traditional American pastime of tinkering with cars is obstructed because cars now contain nonfree software.

Free/Open Licenses Non-free Licenses

This question is broad and not very clear -- with the result that the following answers cover quite different scenarios and use cases.

Functional UNIX[edit] Broadly, any Unix-like system that behaves in a manner roughly consistent with the UNIX specification, including having a "program which manages your login and command line sessions";[14] more specifically, this can refer to systems such as Linux or Minix that behave similarly to a UNIX system but have no genetic or trademark connection to the AT&T code base.

In a broader sense, taxonomy also applies to relationship schemes other than parent-child hierarchies, such as network structures. Taxonomies may then include a single child with multi-parents, for example, "Car" might appear with both parents "Vehicle" and "Steel Mechanisms"