Maybe something simpler would work.

#!perl
use strict;
use warnings;
use autodie; # chdir and open die on error
use File::DosGlob 'glob'; # DOS-style wildcards
use File::Slurp 'slurp';

my $dir = 'c:/mydir/';

my $maxsize = 0;

chdir $dir;

for my $file (glob('*')) {

    # check size
    my $size = -s $file;
    $maxsize = $size if $size > $maxsize;
    print "$_: $size\n";

    # get contents
    my @lines = slurp $_; # one string per line
    #my $lines = slurp $_; # only one string 

    # manipulate contents
    #...
}

# report
print "\n\nmax file size: $maxsize\n";
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