use warnings;
use strict;
use Cwd qw(abs_path);
use File::Find qw(find);

die "no directory provided " unless defined $ARGV[0];
my $path = abs_path $ARGV[0];

find( \&search_all_folder, $path );

sub search_all_folder {
    chomp $_;
    return if $_ eq '.' or $_ eq '..';
    read_files($_) if (-f);
}

sub read_files {
    my ($filename) = @_;

    open my $fh, '<', $filename or die "can't open file: $!";
    while (<$fh>) {
        print $_, $/;
    }
}