A) Short answer

Default groups; say for user123, on fresh install - (use command groups in a terminal):

user123 adm cdrom sudo dip plugdev lpadmin sambashare

Gives diff from 11.04 as

• admin is replaced by sudo


• dialout is removed


• dip is added.

To get/view defaults. Would probably work for various others too; do:

sudo grep user-setup /var/log/installer/syslog

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B) Restoring default groups

(Adding this to make it more complete)

1. Identifying the groups

I always set root password, but if you haven't use a live CD, live USB, other install etc. to get to the file.

If you have set root password (by i.e.):

sudo passwd root

and have lost sudo privileges do:

su - root

grep user-setup /var/log/installer/syslog

Gives you i.e.

... user-setup: pwconv: failed to change the mode of /etc/passwd- to 0600

... user-setup: Shadow passwords are now on.

... user-setup: Adding user `user123' ...

... user-setup: Adding new group `user123' (1000) ...

... user-setup: Adding new user `user123' (1000) with group `user123' ...

... user-setup: Creating home directory `/home/user123' ...

... user-setup: Copying files from `/etc/skel' ...

... user-setup: addgroup: The group `lpadmin' already exists as a system group. Exiting.

... user-setup: Adding group `sambashare' (GID 124) ...

... user-setup: Done.

... user-setup: Adding user `user123' to group `adm' ...

... user-setup: Adding user user123 to group adm

... user-setup: Done.

... user-setup: Adding user `user123' to group `cdrom' ...

... user-setup: Adding user user123 to group cdrom

... user-setup: Done.

... user-setup: Adding user `user123' to group `dip' ...

... user-setup: Adding user user123 to group dip

... user-setup: Done.

... user-setup: Adding user `user123' to group `lpadmin' ...

... user-setup: Adding user user123 to group lpadmin

... user-setup: Done.

... user-setup: Adding user `user123' to group `plugdev' ...

... user-setup: Adding user user123 to group plugdev

... user-setup: Done.

... user-setup: Adding user `user123' to group `sambashare' ...

... user-setup: Adding user user123 to group sambashare

... user-setup: Done.

... user-setup: adduser: The group `debian-tor' does not exist.

... user-setup: Adding user `user123' to group `sudo' ...

... user-setup: Adding user user123 to group sudo

... user-setup: Done.

... ubiquity: Removing user-setup ...

... ubiquity: Purging configuration files for user-setup ...

Or:

su - root

grep "user-setup: Adding user user123 to group" /var/log/installer/syslog | cut -d' ' -f11

Which yields:

adm

cdrom

dip

lpadmin

plugdev

sambashare

sudo

(No idea why dip suddenly has become a default group by install. Something to do with dialout being removed?)

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2.a Updating groups - using "built-in" root access

So do, as root, to add groups to user, i.e. user user123:

usermod -a -G adm,cdrom,lpadmin,sudo,sambashare,dip,plugdev user123

Where (Somewhat outdated on 12.10):

adm         Monitor system logs

cdrom       Use CD-ROM drives

lpadmin     Configure printers

sudo        administer the system, ...

sambashare  Share files with the local network

dip         Connect to the Internet using a modem

plugdev     Access external storage devices

Some extras you might need: (check what you have by root@YOURPC:~# id -nG user123)

dialout     ttyS*/Serial/COM1,COM2 ...

vboxusers   Virtual Box

user123     Your own group

If you want; double-check /etc/group , i.e. (here with some extras):

root@YOURPC:~# grep user123 /etc/group



adm:x:4:user123

audio:x:29:user123,timidity,pulse

video:x:44:user123

lp:x:7:user123

dialout:x:20:user123

cdrom:x:24:user123

sudo:x:27:user123

dip:x:30:user123

plugdev:x:46:user123

lpadmin:x:107:user123

user123:x:1000:

sambashare:x:124:user123

vboxusers:x:127:user123

autologin:x:1001:user123

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As an alternative one can boot in to rescue mode and

mount -o remount,rw /

usermod -G adm,cdrom,lpadmin,sudo,sambashare,dip,plugdev user123

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Log out and log in. Groups should be updated.

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2.b Updating groups - using root access from Live-CD etc.

xxx here is where your file-system is mounted when running a live edition, i.e. /media/foo.

Manually edit the file /xxx/etc/group using vigr and add user as in previous listing.

Or; only add user to sudo; as in:

sudo:x:27:user123

Boot into your installation and update by executing the usermod command with sudo:

sudo usermod -a -G adm,cdrom,lpadmin,sudo,sambashare,dip,plugdev user123

Log out and log in. Groups should be updated.

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Double Note: admin is no longer part of Ubuntu as of 11.10 in favour of sudo.