[ubuntu-uk] backup home folder

[Alan Lord (News)]

On 17/09/10 13:35, alan c wrote:
> On 16/09/10 09:57, Alan Lord (News) wrote:
>> One gotcha that you should be aware of when using a fresh operating
>> system install is that usernames and groups in linux are actually really
>> numbers (UID and GID) and the name is mapped to the UID in /etc/passwd.
<snip />
> To help me be more clear on this:
> Am I correct in understanding that as long as the original
> /home/username
> is copied or backed up while being signed on as first user, then the
> subsequent paste into the new install will be ok?

Hi Alan,

How does this work?

When every user is created on a linux system they are assigned a UID 
number (and usually a GID of the same). These tend to happen 
sequentially so the first user (the one you create when installing 
Ubuntu) will get UID 1000. The next 1001 etc etc - there *may* be gaps 
as some applications might create users when they get installed. 
Although looking at my /etc/passwd it looks as though Ubuntu uses UIDs < 
1000 for applications.

So:

/home/user1 will be stored on the file system with UID/GID of 1000.
/home/user2 1001
/home/user3 1002 etc etc,

It isn't a *major* headache of the UIDs from one system to the next 
don't match when moving a backup, you just have to be aware of this and 
change as necessary: either use:

sudo vipw

to edit /etc/password and change the user's UID/GID to the right ones, or:

sudo chown newuser: -R /home/newuser

I'd be a little more careful with this one in case there are any system 
files/hidden files stored in your home dir. I don't think there should 
be but I'm sure a quick search/find could tell you.

HTH

Al

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