Print the group of files modified within an hour of the most recently modified file

mrmgroup.pl

#!/usr/bin/env perl
# Print the group of files modified within an hour of the most recently
# modified file.

use strict;
use List::Util qw[min max];
use Getopt::Std;

$Getopt::Std::STANDARD_HELP_VERSION = 1;
sub HELP_MESSAGE {
    my $out = shift;
    print $out "usage: mrmgroup [-H HOURS] FILE...\n"
}
sub VERSION_MESSAGE {
}

my %opts = ("H", 1);
getopts('hH:', \%opts); 
if ($opts{h}) {
    my $stdout = *STDOUT;
    HELP_MESSAGE($stdout);
    exit(0);
}

my $delta = $opts{"H"} * 3600;

my %times;
for my $f (@ARGV) {
    my @s = stat $f;
    $times{$f} = $s[9];
}
my $latest = max(values(%times));
for my $f (keys %times) {
    my $mtime = $times{$f};
    if ($latest - $mtime < $delta) {
        print $f . "\n";
    }
}