Resetting ownership

[TuxNewb]

I accidentally chowned my whole filesystem to nobody:nogroup.

Stupid, I know.

I'm wondering if apt keeps a copy of the perms it set during installs like RPM does?

If not, is there any other way to restore the perms easily?

If not, does anyone have a quick screenshot of their root level perms on Debian Hardy? I can at least start with a chown -R of the top level dirs and see how close that gets me.

[hazel]

drwxr-xr-x 2 root root 4096 Apr 26 17:56 bin
drwxr-xr-x 2 root root 4096 Sep 27 2009 boot
drwxr-xr-x 10 root root 3660 May 7 16:24 dev
drwxr-xr-x 22 root root 4096 May 7 16:24 etc
drwxr-xr-x 4 root root 4096 Sep 3 2009 home
drwxr-xr-x 7 root root 4096 Apr 26 17:55 lib
drwx------ 2 root root 16384 Jun 29 2009 lost+found
drwxr-xr-x 6 root root 4096 Jun 29 2009 media
drwxr-xr-x 3 root root 4096 Sep 3 2009 mnt
drwxr-xr-x 10 root root 4096 Oct 4 2009 opt
dr-xr-xr-x 69 root root 0 May 7 16:24 proc
drwxr-x--- 6 root root 4096 Apr 12 11:12 root
drwxr-xr-x 2 root root 4096 Apr 26 17:56 sbin
drwxr-xr-x 12 root root 0 May 7 16:24 sys
drwxrwxrwt 5 root root 120 May 7 17:36 tmp
drwxr-xr-x 11 root root 4096 Apr 26 18:04 usr
drwxr-xr-x 12 root root 4096 Apr 19 22:12 var

[dokma]

How did you manage to do that? It came to my mind that perhaps chown should be interactive when this sort of thing is attempted recursively on any major directory.

[impert]

I accidentally chowned my whole filesystem to nobody:nogroup.

I can promise you that you're not the only one to do this sort of thing.
When I did something similar I lost patience with re-chowning and re-chmod-ing and just re-installed, which is probably the best thing to do. (EDIT) though it would be simpler if only the ownerships are wrong.
On Mac OS/X, where permissions get screwed with monotonous regularity, there is a tool for re-setting the permissions to their default values. I've read that

rpm -a --setperms

works on rpm-based systems. Haven't found anything for Debian and friends.
It strikes me that a script to reset permissions would be a useful addition to the Linux toolbox - I suppose it would have to have options to cover a number of different distros.