# slurp!
my $wholefile = join q{}, <DATA>;

# It's a HoH, I swear!
$wholefile = "\n$wholefile";
$wholefile =~ s{\n(\s*)(\S+)\s*=\s*}{\n$1'$2' =>}g;
$wholefile = "{ $wholefile }";

# DANGER, Will Robinson!
my $d = eval $wholefile;
die $@ if $@;

# Not exactly regular expressions
$d->{'bakjob1_details'}{'debit'}{'customer2'} = 123456;
$d->{'bakjob1_details'}{'credit'}{'customer2'} = 123456;
$d->{'bakjob2_details'}{'debit'}{'customer2'} = 7337.64;
$d->{'bakjob2_details'}{'credit'}{'customer2'} = 7337.64;

output( $d, 2 );

sub output {
    my ( $href, $indent ) = @_;

    foreach my $key ( keys %{ $href } ) {
        my $value = $href->{$key};
        my $in = q{ } x $indent;

        if ( ref $value eq ref {} ) {
            print "$in$key = {\n";
            output( $value, $indent + 2 );
            print "$in},\n";
        }
        else {
            print "$in$key = $value,\n";
        }
    }

    return;
}

__DATA__
  bakjob1_details = {
    credit = {
      customer1= 2000.0,
# I added a comma
      customer2 = -1500.0,
      customer3 = 0.0,
    },
    debit = {
      customer1= 50000.0,
      customer2 = -2000.0,
      customer3 = 0.0,
    }
  },
  bakjob2_details = {
    credit = {
      customer1= 1000.0,
      customer2 = 200.0,
      customer3 = 500.0,
    },
    debit = {
      customer1= 600.0,
      customer2 = 659.0,
      customer3 = 887.0,
    }
  }

##</code><code>##

  bakjob1_details = {
    debit = {
      customer1 = 50000,
      customer3 = 0,
      customer2 = 123456,
    },
    credit = {
      customer1 = 2000,
      customer3 = 0,
      customer2 = 123456,
    },
  },
  bakjob2_details = {
    debit = {
      customer1 = 600,
      customer3 = 887,
      customer2 = 7337.64,
    },
    credit = {
      customer1 = 1000,
      customer3 = 500,
      customer2 = 7337.64,
    },
  },