use warnings;
use strict;
my @a = qw( 2 two 1 11 12 one 3abcd 6foo );
print join( " ", sort { $a <=> $b || $a cmp $b } @a ), "\n";

__END__
Argument "two" isn't numeric in numeric comparison (<=>) at c:\temp\sort.pl line 4.
Argument "one" isn't numeric in numeric comparison (<=>) at c:\temp\sort.pl line 4.
Argument "3abcd" isn't numeric in numeric comparison (<=>) at c:\temp\sort.pl line 4.
Argument "6foo" isn't numeric in numeric comparison (<=>) at c:\temp\sort.pl line 4.
one two 1 2 3abcd 6foo 11 12

##</code><code>##

#...
print join( " ", sort { $a cmp $b || $a <=> $b } @a ), "\n";

__END__
1 11 12 2 3abcd 6foo one two