How do I permute N elements of a list?

Here's a little program that generates all permutations of all the words on each line of input. The algorithm embodied in the permut function should work on any list: 

    #!/usr/bin/perl -n
    # permute - tchrist@perl.com
    permut([split], []);
    sub permut {
	my @head = @{ $_[0] };
	my @tail = @{ $_[1] };
	unless (@head) {
	    print "@tail\n";
	} else {
	    my(@newhead,@newtail,$i);
	    foreach $i (0 .. $#head) {
		@newhead = @head;
		@newtail = @tail;
		unshift(@newtail, splice(@newhead, $i, 1));
		permut([@newhead], [@newtail]);
	    }
	}
    }