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 in-
       stead 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.