shift [ -p ] [ n ] [ name ... ]
       The positional parameters ${n+1} ... are renamed to $1 ..., where  n
       is  an  arithmetic  expression that defaults to 1.  If any names are
       given then the arrays with these names are shifted  instead  of  the
       positional parameters.

       If  the  option  -p  is given arguments are instead removed (popped)
       from the end rather than the start of the array.
