The GNU Astronomy Utilities (Gnuastro) is an official GNU package consisting of separate programs for the manipulation and analysis of astronomical data. All the various utilities share the same basic command line user interface for the comfort of both the users and developers. GNU Astronomy Utilities is written to comply fully with the GNU coding standards so it integrates finely with the GNU/Linux operating system. This also enables astronomers to expect a fully familiar experience in the source code, building, installing and command line user interaction that they have seen in all the other GNU software that they use.