I gotta chime in here and point out that a simple sort with { lc($a) cmp lc ($b) } may not be what you want. You may wish to do a fancier sort like the second one in this example:

#!/usr/bin/perl -w

my @un = <DATA>;
print "once:\n";
print sort { lc($a) cmp lc($b) } @un;
print "\nagain:\n";
print sort { (lc($a) cmp lc($b)) or ($a cmp $b) } @un;

__DATA__
Mark
MARK
mark
Dave
DAVE
DAVEY
Davey
davey
MarkY
[download]