shift

shift @
array

Removes the first value of @array and returns it, shortening the array by 1 and moving everything down. If there are no elements in the array, the function returns the undefined value. If @array is omitted, the function shifts @ARGV (in the main program), or @_ (in subroutines). See also unshift , push , pop , and splice . The shift and unshift functions do the same thing to the left end of an array that pop and push do to the right end.