sub alpha_num_cmp 
{
  my($a, $b) = @_;
  if (( $a =~ m/\D/) || ($b =~ m/\D/) ) { #look for a non-digit
      return ($a cmp $b);  #if so, then use string compare
      }
 return ($a <=> $b); #otherwise straight numeric comparison
}  

##</code><code>##

#!usr/bin/perl -w
use strict;

my @a=(8,5,2,4,88,1,10,20,5,4,3,2);

my @b = sort @a;
print "alpha sort\n";
print "@b\n";

@b = sort {$a<=>$b}@a;
print "numeric sort\n";
print "@b\n";

@b = sort alpha_num_cmp @a;
print "an any sort\n";
print "@b\n";

sub alpha_num_cmp 
{
   if ( ( $a =~ m/\D/) || ($b =~ m/\D/) ) 
   {                       #look for a non-digit
      return ($a cmp $b);  #if so, then use string compare
   }
   return ($a <=> $b); #otherwise straight numeric comparison
}

__END__
prints:
alpha sort
1 10 2 2 20 3 4 4 5 5 8 88
numeric sort
1 2 2 3 4 4 5 5 8 10 20 88
an any sort
1 2 2 3 4 4 5 5 8 10 20 88