[CentOS] migrating users from linux to centos

Barry L. Kline blkline at attglobal.net
Tue Jul 24 18:46:35 UTC 2007

Hash: SHA1

simon wrote:
> Dear All,
> I have been running linux 9 server as a dns and mail server and is workin
> fine..
> i want to install CENTOS 5 with all the latest mail server software and
> bind as well as all the libraries on another machine whic is already done
> also the data is backed up and will be tranferred.
> but i would like to know
> i have about existing 100 mail users
> how could i tranfer these usernames and passwrd to the new CENtos 5 server ..
> if i copy the /etc/passwd from my linux server it gonna overite my centos5
> /etc/passwd file as there r new users n also new groups create when i
> installed centos5 n software
> also i see that the /etc/shadow has only read permisson for root so cant
> be over written
> is there a way i cd possiblly have the existing users with thier password
> on centos5 so i dont have to ask them for their passwords n create all
> users again

Create copies of /etc/{passwd,shadow,group} from the original system.
Edit the copies to EXCLUDE existing user/groups.
Append the remaining entries to the existing file.


cp /etc/passwd /etc/passwd.old   # from the old system
vim passwd.old  (and edit out the existing entries)
copy passwd.old   to the new system
cat passwd.old  >> /etc/passwd   (notice the '>>')

Repeat for group & shadow.


Version: GnuPG v1.2.6 (GNU/Linux)


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