keepsz --limit=100M --folder=/var/log/cups/*.gz

keepsz --generator=50

#!/usr/bin/perl -w
use strict;
use Getopt::Long;
use bigint;

sub usage () {

    print <<EOF;

USAGE:

Counts size of files pointed by mask in <folder> and delete older files
if total size of files is greater than <limit>

    $0 --limit=100M --folder=/var/log/cups/*.gz
        or
    $0 --generator=100 ( generates 100 files in subdir ./100-files just for testing )

( you can add letters K, M, G to number for Kilo-, Mega- or Giga- bytes )

EOF

    exit;
}

sub get_limit(@);
sub generator(@);


my $limit       = '1275';
my $folder      = '50-files/*';
my $help        = 0;
my $verbose     = 0;

GetOptions (

    "verbose"     =>   \$verbose,
    "folder=s"    =>   \$folder,
    "limit=s"     =>   \$limit,
    "generator=i" =>   \&generator,
    "help|?"      =>   \&usage,

) or usage();

my $limit_bytes = get_limit($limit) or usage();
my $total_files = 0;
my $sum_bytes   = 0;
my $deleted     = 0;
my @mustdie
   =   
       grep { ($sum_bytes > $limit_bytes) and ($sum_bytes -= $_->{'size'}) }
       sort { $b->{'mdate'} <=> $a->{'mdate'} }
       map  { { name => $_, mdate => -M, size => -s } }
       map  { $sum_bytes += -s; $total_files += 1; $_ } 
       grep { -f }
       glob $folder;

for ( @mustdie ) {

    if ($verbose ) {
        warn sprintf "File %40s, having size %s last modified %s days ago, will be deleted",
                     $_->{'name'},
                     $_->{'size'},
                     $_->{'mdate'};
    }
    $deleted += unlink $_->{'name'} or warn $!;
}

print  "Total $total_files files, ",  scalar @mustdie,
          " file(s) proceeded, $deleted files deleted, keeping $sum_bytes bytes\n";


sub generator(@) {

    my ($opt_name, $count ) = @_;
    mkdir "$count-files";
    my $total_size = 0;
    unlink glob "$count-files/*";
    
    for ( my $j=1; $j <= $count; ++$j ) {
        open F, ">", sprintf("$count-files/%0*d", length $count, $j) or die $!;
        print F '.' for 1 .. $j;
        $total_size += $j;
    }
    
    print <<EOF;

$count files resides in the folder $count-files with total size $total_size.
Now you can add some file(s) with arbitrary size to this folder and run:

$0 --folder=$count-files/* --limit=$total_size

( old files should be deleted to fit in total's size $total_size. check it)

EOF


    exit($count);

}


sub get_limit(@) {
    
    my $limit_str = uc shift;

    my %kmg = ( K=>1024, M=>1024*1024, G=>1024*1024*1024, 1=>1 );

    $limit_str =~ / (\d+) ([KMG])* /x;
    
    return $1 * $kmg{ $2 or '1' }; 
}