use strict;
use warnings;
use YAML;
use Data::Dump;

my %configHash = (
    cat => 'Fred',
    dog => 'Joe',
);

my $cfgFileContents = YAML::Dump(\%configHash);

Data::Dump::dump (\%configHash);

print $cfgFileContents;
$cfgFileContents .= "cat: Bob\n"; # User added configuration entry

my $loaded = YAML::Load($cfgFileContents);

Data::Dump::dump ($loaded);

$cfgFileContents = <<DATA;
---
cat:
  - Fred
  - Bob
dog: Joe
DATA

$loaded = YAML::Load($cfgFileContents);

Data::Dump::dump ($loaded);