simple example of the power File::Find

p-find.pl

#!/usr/bin/env perl 
use Modern::Perl;
use File::Find;

#--------------------------------------------------
# no getopt since its very simple
#-------------------------------------------------- 
die "Enter a directory to search\nUsage: perl $0 <dir_path>" unless @ARGV;

my $total_size = 0;
find(sub { $total_size += -s if -f }, $ARGV[0]);

say $total_size;