Perl script help (Usage alert)

#!/usr/bin/perl
 
use File::Find ("find");
use strict;
 
my (%time, @dirs, $total, $atime, $mtime, $ctime, $aflag, $cflag, $mflag, $tflag);
 
$mtime=0;
$ctime=0;
$atime=0;
 
while (1) {
        last unless $_=shift;
        if (/^-a$/) {$aflag=1; $atime=shift; exit 1 unless $atime =~ /^\d*$/}
        if (/^-m$/) {$mflag=1; $mtime=shift; exit 1 unless $mtime =~ /^\d*$/}
        if (/^-c$/) {$cflag=1; $ctime=shift; exit 1 unless $ctime =~ /^\d*$/}
        if (/^-t$/) {$tflag=1;}
        push @dirs,$_ unless /^-/;
}
die {"Usage: $0 [-a <Days>,-m <Days>,-c <Days>] /Filesystem_pathname (Refer ReadMe file) \n"} unless $aflag || $cflag || $mflag;
 
die {"Usage: $0 [-a <Days>,-m <Days>,-c <Days>] /Filesystem_pathname (Refer ReadMe file) \n"} unless @dirs;
 
for (@dirs) {
        print "\n ==> $_\n\n";
        find(\&wanted, $_);
        if ($tflag) {printf "\nTotal size of resultant files: %8.2f MB\n\n", $total / (1024 * 1024)};
        $total = 0;
}
 
sub wanted {
        if ($_ eq ".snapshot") {
                $File::Find::prune=1;
           }
        elsif ((-f || -d ) && -A > $atime && -C > $ctime && -M > $mtime)
           {
                my $size = -s;
                $total += $size;
                print `ls -l $File::Find::name`, "\n";
          #printf "%-75s\t%7d KB\n", $File::Find::name, ($size / 1024);
           }
}