shift(ARRAY)

     shift ARRAY

     shift

             Shifts the first value of the array off and  returns
             it,  shortening the array by 1 and moving everything
             down.  If  there  are  no  elements  in  the  array,
             returns  the  undefined value.  If ARRAY is omitted,
             shifts the @ARGV array in the main program, and  the
             @_  array in subroutines.  (This is determined lexi-
             cally.)   See  also  unshift(),  push()  and  pop().
             Shift()  and unshift() do the same thing to the left
             end of an array that push()  and  pop()  do  to  the
             right end.