There is more than one way to do this, and the "correct" way depends on the minute details of your setup. Here's the code i use in my framework (this isn't exactly from the most modern module i have, but it works):

# Use the object oriented version of stat
use File::stat;
...

sub _dircleaner($self, $dir, $maxagedays) {
    my $reph = $self->{server}->{modules}->{$self->{reporting}};

    $reph->debuglog("Scanning $dir for cleaning");

    my @todelete;
    my $deletes = 0;
    my $ok = 1;

    my $dfh;
    if(!opendir($dfh, $dir)) {
        $reph->dblog("DIR_CLEANER", "Can't open '$dir'");
        $dbh->commit;
        $reph->debuglog("Can't open $dir");
        $ok = 0;
        goto finishcleaning;

    }

    my $fcount = 0;
    my $maxage = $maxagedays * 3600 * 24; # Convert days to seconds
    my $now = time();
    while((my $fname = readdir($dfh))) {
        next if($fname eq "." || $fname eq "..");

        # FIXME FOR SUBDIRS! CLEAN UP SUBDIRS, THEN REMOVE ALL EMPTY D
+IRS

        next if(!-f "$dir/$fname");
        my $fileage = stat("$dir/$fname")->mtime;
        my $age = $now - $fileage;
        next if($age <= $maxage);
        push @todelete, "$dir/$fname";
        $fcount++;
    }
    closedir($dfh);

    if($fcount) {
        $reph->debuglog("Cleaning $fcount file(s) in $dir");
        foreach my $fname (@todelete) {
            if(unlink $fname) {
                $deletes++;
                $reph->debuglog("   ...deleted $fname");
            } else {
                $ok = 0;
                $reph->debuglog("Failed to delete $fname");
            }
        }
        $reph->debuglog("Deleted $deletes file(s).");
    }

finishcleaning:
    return $ok;
}
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Basically, i read the whole directory in and remember the files i want to delete, then delete them one-by-one. The relevant steps for filtering the files is:

# Convert age (in days) to seconds
my $maxage = $maxagedays * 3600 * 24; # Convert days to seconds

# get the "last modified" timestamp of the file in SECONDS (unix times
+tamp)
my $fileage = stat("$dir/$fname")->mtime;

# Current time in seconds (unix timestamp)
my $now = time;

# Age in seconds
my $age = $now - $fileage;

# Ignore file if it is too new
next if($age <= $maxage);

# Add files to the "@todelete" list with full filename
push @todelete, "$dir/$fname";
[download]