Hi

Not using File::Stat, and using the 'core' stat, may be one solution

use Modern::Perl;

my @files = qw {
        ./adt1.pl
        ./adt2.pl
    }; 

my $color;
my $cur_time = time;
my @quake_times = qw( 21600 3600);

say 'Current time: ', $cur_time;

foreach my $a_filename(@files)
{
            #stat() on the file name
    my $mtime = (stat($a_filename))[9];
    say $a_filename, ", " , $mtime;

     if (($cur_time - $mtime) > $quake_times[1]) {
        $color = 'red';
    }
    elsif (($cur_time - $mtime) > $quake_times[0]) {
            $color = 'yellow';
    }
    else {
               $color = 'green';
    }
    say ("color is ", $color, "\n");
}
[download]

The code above outputs:

~/perl/ex/perlmonks: perl ./adt5.pl 
Current time: 1372263479
./adt1.pl, 1372261299
color is green

./adt2.pl, 1372262161
color is green
[download]

I hope this helps

Arnaud