[CentOS] moving from RH8 to CentOS5.1

Mon Mar 24 23:06:37 UTC 2008
Warren Young <warren at etr-usa.com>

Ray Leventhal wrote:
> 
> Is there a way to 'automatically' recreate users/permissions when moving 
> from RH8 (yes, I know...way old) to CentOS5.1 or is it just simpler to 
> recreate the users manually?

Merge your RH8 copies of /etc/passwd and /etc/shadow into the CentOS 
ones, preferring the new versions of existing users where possible.  Be 
sure not to duplicate user IDs.  Basically, it should be possible to 
copy everything with user ID over 500 directly.  UID 500 will be the 
first user the CentOS firstboot routine makes you add, which you'll 
probably want to remove so you can copy the old UID 500 over.  Anything 
under 500 should probably be left alone on the new box, but you may need 
to merge some under-500's from the old box that don't have a counterpart 
on the new one.

Then, you can use a Unix-aware archiving tool like tar or cpio to pack 
up the user files on the RH8 box.  When you unpack it on the CentOS 
side, it will see that these users are declared in /etc/passwd and 
restore the old permissions and ownership info.  You should study the 
tar or cpio man pages to understand the options you will need to pass to 
make this happen; I'm not certain that it's automatic in all cases.

If you will have network connectivity between the boxes, you might not 
even have to make an extra copy of the files.  Something like this might 
work:

# find /home | cpio -pud | nc newbox ....

then on the other box, you catch the CPIO stream with another copy of nc 
and spit it out to the filesystem with something like cpio -icvBud ...