Date: Wed, 21 Aug 2013 11:36:11 -0500 From: Mark Felder <feld@FreeBSD.org> To: freebsd-questions@freebsd.org Subject: Re: Renumber users and groups Message-ID: <1377102971.29516.12511917.7D1FFD58@webmail.messagingengine.com> In-Reply-To: <5214E6EB.30102@fjl.co.uk> References: <u9zjsb8bkz.fsf@banyan.cs.ait.ac.th> <5214E6EB.30102@fjl.co.uk>
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On Wed, Aug 21, 2013, at 11:12, Frank Leonhardt wrote: > On 21/08/2013 13:36, Olivier Nicole wrote: > > Hello, > > > > On my system legacy users come with UID starting from 200 upward, and > > all users come with GID lower that 100. > > > > I know it's not a good idea, but consider that some accounts are over 20 > > years old! > > > > This is not too much a problem with FreeBSD as I can renumber the few > > FreeBSD services that have a conflicting ID. > > > > But now I want to share the user directories with Mac (10.6). On Mac, > > any id lower than 512 should be reserved for the system. > > > > I tried to renumber the conflicting services on Mac OS, but it messes up > > the system. > > > > So I should renumber my users; it's not very difficult to do, but I have > > over 1TB of user files for 200 users. > > > > Is there a clever/fast way to do that (other than find -exec chown)? > > > > What pitfall should I avoid? > > > > Best regards, > > > > Olivier > > Both tar and rsync are spectacularly clever about this. I've never > needed to renumber users, but I've noticed tar will restore a backup > across hosts and try to resolve user names correctly. tar stores users > and groups symbolically and will happily extract them to the correct > numerical ID on the new host. All you need do, therefore, is merge the > passwd and group files without conflict and "untar" everything. If > you've got to do this in-place it's not going to work, but as you'd be > wise to make a backup anyway you may as well make a copy instead, and > let it convert them on the fly. rsync seems to pull the same trick. > Those solutions sound pretty handy if I need to move the files at the same time. mtree should do this in-place with minimal fuss as it's just confirming permissions and ownership on all files.
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