in reply to Changing Perl's sort Default

Probably the most concise, direct description of how to "customize" the behavior of sort can be found here:
perldoc -f sort
That will print out just the portion of the massive "perlfunc" man page that discusses the "sort" function.

BTW, when you say "alphanumerical", do you really mean "case-folded"? The output of the above command contains the answer.