I think davido's approach is the cleanest/easiest. However, I would avoid the "sort" - since you are creating "@ordered_keys" anyway, why not store them in the right order as they are entered into the hash ?

my %hash;
my @ordered_keys;
while ( my $line = <DATA> ) {
    chomp $line;
    next unless $line;
    my ( $key, $value ) = split /\s*=\s*/, $line;
    $hash{$key} = $value;
    push @ordered_keys, $key;
}
# No need to sort - @ordered_keys is already in the right sequence...
print "$_ = $hash{$_}\n" for @ordered_keys;
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Of course, this begs the question - why use %hash at all - hopefully, you have a reason for that - need quick/random reference to the keys for an unstated reason.