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.