I ran this command on my ubuntu 12.04 by mistake:
chown someuser / -R
On RHEL it would be fixed by this command:
rpm --setugids -a
Is there anyway to fix it in ubuntu server?
There is not an straight forward way to do it, as far as I know. This answer can probaly help you a bit: http://superuser.com/questions/132891/how-to-reset-folder-permissions-to-their-default-in-ubuntu-9-10