keep n more recent files in directory

keepn

#!/usr/bin/perl
#description: keep n more recent files in directory
#usage: keepn DIR <n>

#exampe: keepn /var/log/apt/ 15 #default to 10
#keep latest 15 files, remove the rest

use strict;
use warnings;
use File::Basename;

my $progname  = basename(__FILE__);
my $default_n = 10;

sub _usage {
    print "Usage: " . $progname . " DIR <n>\n";
    print "Keep n more recent files in directory.\n\n";
    print "  -h, --help   show this help message and exit\n";
}

sub _die {
    print  STDERR "@_\n" if (scalar(@_) > 0);
    select STDERR; _usage(); exit 1;
}

sub _keepn {
    my ($dir, $n) = @_;
    $n = $default_n if not defined $n;

    if ( ! -d $dir) {
        _die("Directory '" . $dir . "' doesn't exists!");
    }

    my @newest_first =
        map $_->[0],
        sort { $a->[1] <=> $b->[1] }
        map [$_, -M],
        < $dir/* >;
        unlink @newest_first[$n..$#newest_first]
    if @newest_first > $n;
}

_die() unless @ARGV;

foreach (@ARGV) { #parse options
    ($_ eq '-h' || $_ eq '--help') && do { _usage() && exit };
    ($_ =~ /^-./) && do { _die("$progname: unrecognized option '$_'") };
}

_keepn @ARGV;

Cron usage:

* * * * * /path/to/keepn   /path/to/logs/directory  100 #keep latest 100 files, delete all others