sub n {
    $_[0] =~ m#^(\d+)-(\d+)-(\d+)(.*)#;
    sprintf( "%02d%02d%02d%s",$3,$1,$2,$4 );
}
my @line = sort {n($a) cmp n($b)} <DATA>;
print @line;
__DATA__
1-22-03 somedata_somedata
1-23-03 wwwwwwwwwww
1-22-03 sssssssssssss
2-3-03 aaaaaaaaaaaa
1-3-03 sdddddd
2-3-03 ddddddddddddd
1-22-03 eeeeeeeeeee
2-3-03 hhhhhhhhh
1-3-03 kkkkkkkkkkkkkkk
2-3-03 llllllllllllllll