all - alles; how to understand specific one - all?

Question

I'm watching the movie "Who am I - no system is safe" to learn German. the contex is:

Wenn ich gewusst hätte, wie all das ausgehen wird… hätte ich alles anders gemacht.

I've read a post about this How to know which form of "all, alle, allen, aller, allem, alles" to use? but still not clear for my case. My understanding is:

1) alles - everything, express an genreal idea about something. Is that correct?

2) all - i'm not clear in this. pls explain why they use all in this sentence?

3) Any tip for me about this specifice one - all? I understand about declination but still totaly confuse in this.

Thanks for your help,

Answer 1

»All das« is a synonym phrase for »das alles«. When ever you can use »das alles« (all of this), then you also can use the phrase »all das« instead. Sometimes you also can replace »alles« (without leading »das«) with »all das«. So this would also be a correct version of your sentence:

Wenn ich gewusst hätte, wie das alles ausgehen wird… hätte ich all das anders gemacht.

But in this example now you have twice »das« near »all/alles« which is bad style, so you better leave out one »das«. But this can't be the »das« behind »all«, because »all das« has a different meaning than »all« alone. So you leave out the first »das«:

Wenn ich gewusst hätte, wie alles ausgehen wird… hätte ich all das anders gemacht.

Both versions are grammatical correct, but still the version you heard in the movie ist the one with the best style.

Answer 2

The key to your understanding might be that in the first place "all" stands together with the pronoun (das), and should therefore not be inflected, in the second place "all" stands alone and is inflected strongly like an adjective.