On Sat, Oct 15, 2005 at 06:28:53AM +0200, Rafael Fern?ndez L?pez wrote:
>    Hi,
>    My suggestion for portage is: when you do an "emerge -vuD world", you
>    have to work at the end of the emerging with the /etc config files and
>    see the differences to know if you want to overwrite file by file or
>    not.
>    Well, what I want is to have a backup of all them (one backup, and
>    only one). For that goal, it can be used a new option in make.conf
>    like "backup_etc_files=yes" if you want to turn this on.
>    By turning this on, an "emerge -vuD world" can be done in one shot, I
>    mean, you can do an emerge -vuD world, and all the files could be
>    replaced (overwrited) by the new ones (etc-update), but you'll be able
>    to access to your backups if anything is wrong, so you don't have to
>    go file by file looking at the differences between them.
>    I suggest to name them "whatever.conf" (our original file) ==>
>    "whatever.conf.backup" (our backuped file)
This breaks down pretty quickly... a peacemeal pam upgrade, for 
example can result in you locked out of your system.

Baselayout updates to /etc/passwd can accomplish the same thing, and 
not accounting for /etc/fstab resulting in an unbootable system...
~harring