use warnings; use Date::Manip::Date 6.30; 
my$base = Date::Manip::Date->new; $base->config("setdate" => "now,utc");
my $delta = $base->new_delta("-30 days"); 
open my$infile, "<", "in.txt" or die; 
while (<$infile>) { 
    my$cur = $base->new; 
    my $parse_err = $cur->parse_format(q"\w+ %b %d %H:%M:%S %Y", $_); 
    if ($parse_err) { 
        1; # input line does not contain a valid date, just skip it
    } else { 
        my$mod = $cur->calc($delta); 
        print $mod->printf("%a %b %d %H:%M:%S %Y"); 
    } 
    print "\n"; 
}
__END__

##</code><code>##

Thu Feb 28 10:00:00 2013
Wed Feb 27 10:00:00 2013
Tue Feb 26 10:00:00 2013