Backup Restore: UID & GID are present

leebrent · 11-12-2007, 02:54 AM

Hello,

I have restored a backup of some files onto my server. The server is no empty of users, but the backups are restored using the right UID's and GID's. Is there a trick to recreating all the users and associating them with their UID's and GUID's easily?

Here is an example:

drwxrwx--x 3 3039 3039 4096 Oct 23 10:56 group13
drwxrwx--x 3 3040 3040 4096 Oct 23 10:56 group14
drwxrwx--x 3 3041 3041 4096 Oct 23 10:56 group15
drwxrwx--x 3 3042 3042 4096 Oct 23 10:56 group16
drwxrwx--x 3 3043 3043 4096 Oct 23 11:12 group17
drwxrwx--x 3 3044 3044 4096 Oct 23 10:56 group18
drwxrwx--x 3 3045 3045 4096 Oct 23 10:56 group19
drwxrwx--x 3 3028 3028 4096 Oct 23 10:55 group2
drwxrwx--x 3 3046 3046 4096 Oct 23 10:56 group20
drwxrwx--x 3 3029 3029 4096 Oct 23 10:55 group3
drwxrwx--x 3 3030 3030 4096 Oct 23 10:55 group4
drwxrwx--x 3 3031 3031 4096 Oct 23 10:56 group5
drwxrwx--x 3 3032 3032 4096 Oct 29 12:11 group6
drwxrwx--x 3 3033 3033 4096 Oct 23 11:17 group7
drwxrwx--x 3 3034 3034 4096 Oct 23 10:56 group8
drwxrwx--x 3 3035 3035 4096 Oct 23 10:56 group9

At one time, 3039 = group13:group13. Any help would be greatly appreciated, does someone already have a script?

--B

jschiwal · 11-12-2007, 04:50 AM

If you had also backed up the /etc/passwd & /etc/shadow files, you could restore them somewhere and extract the regular users and then append those lines to your current files.

This bit isn't tested. I just saved your sample to a file and used awk to display the uid, gid and user fields. This will create inactive accounts (no passwords) disabled with "!" in the passwd field.

Code:

while read uid gid user; do
   groupadd -g=$gid $user 
   adduser -u=$uid -g=$gid -f $user
done < <(ls -ld | awk '{print $3, $4, $9}' )

leebrent · 11-12-2007, 09:21 AM

Quote:

Originally Posted by jschiwal

If you had also backed up the /etc/passwd & /etc/shadow files, you could restore them somewhere and extract the regular users and then append those lines to your current files.

This bit isn't tested. I just saved your sample to a file and used awk to display the uid, gid and user fields. This will create inactive accounts (no passwords) disabled with "!" in the passwd field.

Code:

while read uid gid user; do
   groupadd -g=$gid $user 
   adduser -u=$uid -g=$gid -f $user
done < <(ls -ld | awk '{print $3, $4, $9}' )

I have the shawdow and passwd files here in my backup. So I can just append the lines for the regular users to the end of the existing files and that will be that?

leebrent · 11-12-2007, 02:09 PM

Quote:

Originally Posted by leebrent

I have the shawdow and passwd files here in my backup. So I can just append the lines for the regular users to the end of the existing files and that will be that?

I ended up using this script, thanks to your information. I was able to build it:

#This is only useful if authenication takes place from an external source like LDAP, and the user does not have a password stored on the local machine.

ls -la /home > USERS
cat USERS | awk '{print "groupadd -g", $4, $9}' > part1.sh
cat USERS | awk '{print "useradd -u", $3, $9, "-g", $9 }' >> part1.sh
chmod 775 part1.sh
echo "Now go check Part1.sh, and remove any bad users"
echo "."
echo "Once checked, then run ./part1.sh"