Does the opposite of a shift. Or the opposite of a push, depending on how you look at it. Prepends list to the front of the array, and returns the new number of elements in the array.

    unshift(@ARGV, '-e') unless $ARGV[0] =~ /^-/;

Note the LIST is prepended whole, not one element at a time, so the prepended elements stay in the same order. Use reverse to do the reverse.