Bash exception to GPL

The Free Software Foundation has exempted Bash from the requirement of
Paragraph 2c of the General Public License.  This is to say, there is
no requirement for Bash to print a notice when it is started
interactively in the usual way.  We made this exception because users
and standards expect shells not to print such messages.  This
exception applies to any program that serves as a shell and that is
based primarily on Bash as opposed to other GNU software.