[Nix-dev] confusing rollback / generation system

[Vladimír Čunát]

On 05/18/2017 11:27 PM, Stefan Huchler wrote:
>> You don't need to.  You can run just `nix-env --rollback` repeatedly to
>> get to the generation you want.  Note that it's just a linear list; that
>> might have "confusing consequences" when you alternate appending items
>> with rollbacks.
> with nix-env --list-generations I get that 15-19 generation stuff so
> nix-env rollback would operate on that right?

Right.

> So I need to give the system-path to operate on... to take actions on
> it. I dont see how to get around that...

Oh, you mean the system-wide profile?  (i.e.
/nix/var/nix/profiles/system)  That's the root's profile.  If you use
`nix-env` as root, it will operate on that by default.  You typically
need elevated privileges, but it's probably possible to change
permissions of that directory...

--Vladimir