use strict;
use warnings;
print sort { ($a =~ m/\S+\s+(.+)$/)[0] cmp ($b =~ m/\S+\s+(.+)$/)[0] }
+ <DATA>;

__DATA__
vmk032    2013-07-24 11:27:38
RRsnap02  2013-07-24 12:35:35
vmk000    2013-07-22 17:16:50
vmk001    2013-07-22 20:00:36
vmk009    2013-07-23 18:21:12
vmk010    2013-07-23 18:31:00
vmk020    2013-07-23 23:30:43
vmk024    2013-07-24 03:27:30
vmk031    2013-07-24 10:27:36
vmk032    2013-07-24 11:27:38
[download]