$ ls -l monlog.txt
-rw------- 1 h h 10755194 2008-05-30 12:59 monlog.txt
$ perl -le 'print scalar localtime((stat)[9]) for @ARGV' monlog.txt
Fri May 30 12:59:45 2008
$ perl -MFile::stat -le 'print scalar localtime(stat($_)->mtime) for @ARGV' monlog.txt
Fri May 30 12:59:45 2008