Many of the programs in the system are licensed under the GNU General Public License , often simply referred to as “the GPL”. The GPL requires you to make the source code of the programs available whenever you distribute a binary copy of the program; that provision of the license ensures that any user will be able to modify the software. Because of this provision, the source code 1 for all such programs is available in the Ubuntu system. 

There are several other forms of copyright statements and software licenses used on the programs in Ubuntu. You can find the copyrights and licenses for every package installed on your system by looking in the file /usr/share/doc/ package-name /copyright once you’ve installed a package on your system. 

For more information about licenses and how Ubuntu determines whether software is free enough to be included in the main distribution, see the Ubuntu License Policy (http://www.ubuntu.com/ubuntu/licensing). 

The most important legal notice is that this software comes with no warranties . The programmers who have created this software have done so for the benefit of the community. No guarantee is made as to the suitability of the software for any given purpose. However, since the software is free, you are empowered to modify that software to suit your needs — and to enjoy the benefits of the changes made by others who have extended the software in this way. 

