What's the fastest way to get directory and subdirs size on unix using Perl?

Question

I am using Perl stat() function to get the size of directory and its subdirectories. I have a list of about 20 parent directories which have few thousand recursive subdirs and every subdir has few hundred records. Main computing part of script looks like this:

sub getDirSize {
my $dirSize = 0;
my @dirContent = <*>;

my $sizeOfFilesInDir = 0;
foreach my $dirContent (@dirContent) {
   if (-f $dirContent) {
        my $size = (stat($dirContent))[7];
        $dirSize += $size;
   } elsif (-d $dirContent) {
        $dirSize += getDirSize($dirContent);
   } 
}
return $dirSize;
}

The script is executing for more than one hour and I want to make it faster.

I was trying with the shell du command, but the output of du (transfered to bytes) is not accurate. And it is also quite time consuming. I am working on HP-UNIX 11i v1.

Answer 1

With some help from sfink and samtregar on perlmonks, try this one out:

#!/usr/bin/perl
use warnings;
use strict;
use File::Find;
my $size = 0;
find( sub { $size += -f $_ ? -s _ : 0 }, shift(@ARGV) );
print $size, "\n";

Here we're recursing all subdirs of the specified dir, getting the size of each file, and we re-use the stat from the file test by using the special '_' syntax for the size test.

I tend to believe that du would be reliable enough though.