Alan Browne <alan....@FreelunchVideotron.ca> wrote:
> On 2013.09.26 19:01 , David Empson wrote:
[...]
> > If your old computer only has one account, it is probably user ID 501.
>
> It is still 501. Admin is 502. Guest is 201 (I don't think I ever ran
> that).
The guest account has its home folder deleted each time it logs out, so
it isn't important for migration. Normal and admin accounts created by
System Preferences are numbered sequentially starting at 501.
Other methods of creating accounts may use different number ranges, e.g.
Workgroup Manager (for Mac OS X Server) seems to default to using 1001
and up, but you can specify the ID when creating the account.
[...]
> Thanks David,
>
> Unless I really misunderstood the UUID bit above, I assume that if the
> new account on the new machine is UUID 501
"UUID" and "User ID" are different things. The UUID is a Universally
Unique Identifier (basically a random 128-bit number) which is
guaranteed to be unique to all accounts on one system, and has a very
low probability of matching one generated elsewhere.
The "User ID" is a small number (may be limited to 16 bits, might be 32)
which has the same value on all systems for certain system accounts
(e.g. root) and almost always overlaps for user-created accounts on
different systems, but is unique per account within one system.
I don't know how Mac OS X uses the UUID for an account, but it is
visible in the Advanced Options for the account in System Preferences,
and I've been aware of its existence since Leopard (it may have been
introduced when Apple switched from NetInfo in 10.4 and earlier to
Directory Services in 10.5 and later).
> (and that's what should be created) and the current account on the current
> machine is also 501 that all files in:
>
> - Documents
> - Music
> - Pictures
> - Movies
> - Dropbox
> - Public
>
> can be manually copied after Migration and be usable by the "new" 501
> (same permissions)
Public has one issue to watch: the Drop Box in there has unusual
permissions (others can write but not read), and that might be modified
when copying using Finder, but the rest of those folders should be OK.
On further reflection, using Finder to do a manual migration is likely
to NOT preserve unusual permissions: it probably sets up default
permissions on all copied files. I tend to use cloning or command line
tools (as root) for this sort of operation, and they usually preserve
ownership and permissions.
The headache is the Library folder in the home folder on the source
machine. Migration/Setup Assistant knows which bits don't need to be
copied, but is a lot of fiddly work to get it right when copying
manually. You also can't copy some of it while logged in as that user on
the destination machine, because parts of it will be in use while you
are trying to replace them. That basically forces you to log into a
different account and use root privileges to copy the Library folder of
your user account, e.g. with something like ditto from the command line.
There are also likely to be several hidden files and folders in your
home folder, some of which might be important to copy.
Migration takes care of all of this, and gets most of it right. (My main
account has been migrated, upgraded or cloned from 10.2 through each
major OS version up to 10.8, spanning four computers and a few drive
replacements; I've had minor niggles once that I recall, relating to
some low level tweaks I'd done.)
If the downtime needed for migration during initial setup is a concern,
just move the contents of some big folders out of your home folder on
the source machine before doing the migration, and then you can copy
them at your leisure.
In this scenario, I'd recommend leaving the standard Documents, Music,
Pictures, Movies and Public folders where they are: they have special
permissions, which you might break by moving them, and could end up with
slightly incorrect ones created automatically on the new machine. Move
selected content out of those folders to a temporary folder somewhere
outside the home folder.
> I assume the non-OS included apps will come with Migration (as I'll
> leave that checked)
Yes. Migration/Setup Assistant knows not to copy the standard apps, also
which ones to skip that vary between OS versions (not applicable here).
> As to ACL's I could remove them from the old machine before the last
> backup I suppose (I have a few folders there (Music, Movies, Dropbox,
> Public, iTunes Music)) just to be clean.
Mac OS X sets up ACLs on several folders in your home folder, e.g. to
protect you against accidentally deleting Documents and similar folders.
I wouldn't recommend removing all ACLs.
> This gives me more inclination to setup the account on the new machine
> using Migration (for the apps, etc, but not my data) and then pull those
> over at leisure.
> I'd just have to be sure the new Account is 501 before copying the files.
>
> Can (should) I rename my old machine "AlanMac" to something different first?
The computer name must be unique on the network. If you transfer network
settings during setup it may try to copy the name, and end up with a
"(2)" on the end. Up to you whether you fix this before or after.
The computer name is also used in some contexts such as Time Machine. If
you connect the same backup drive to the new machine, TM will ask if you
want to inherit its backups and keep using the same drive, but this
sometimes results in glitches like only being able to see history for
your new machine, even though the older backups are still there. I've
tended to put my old TM backup drives into storage and started a new one
when I've done a switch to a new computer, especially if the old backup
drive was mostly full. My current one is much bigger so I'll probably
continue using it on my next computer upgrade (possibly next month, if I
like the new rMBPs).
> Can (shouldn't) I rename my old account "AB" to something different first?
I don't see any need to fiddle with the account name. Changing the
account name or home folder name is also something that has to be done
carefully or you will break something.
--
David Empson
dem...@actrix.gen.nz