The copyright licensing notice below applies to this text. Any software described in this text has its own copyright notice and license, which can usually be found in the distribution itself. Permission is granted to copy, distribute, and/or modify this document under the terms of the GFS Free Documentation License, Version 1.2 or any later version published by the Global Free Software; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts.