[SOLVED] HELP -Major User Screwup With usermod. Can It Be Fixed or Reinstall?

[mhumm2]

I haven't broken my system in over 10 years, but I think did today. While trying to install the CHIRP ham radio programmer, I accidentally deleted all my groups except dialout.

I ran $sudo usermod -G dialout username instead of $sudo -aG dialout username. When I rebooted, the only group I am a member of is dialout which means I am unable to sudo for anything.

Is there any way to recover from this and reinstate my groups such as adm so I can perform root tasks or do I have to reinstall the system?

Laughter is expected and I'll even laugh with you if you can help me fix it without a complete reinstall of the system.

[claydoh]

You can boot into recovery mode, and use the 'root' option, which will take you to a root shell and fix things from there. No sudo needed.

https://wiki.ubuntu.com/RecoveryMode

Or, if you want it to be more complicated, boot to a live usb and chroot into the system and then fix things
https://help.ubuntu.com/community/LiveCdRecovery
You will need to know which partition(s) you need to use for this method.

[mhumm2]

claydoh, you're the man! Thank you so much. I'm filing those instructions in case I ever do something like that again. I don't know what other groups I need to be a member of, but I can sudo so I can administrate and configure my system again. Thanks and Merry Christmas.

[claydoh]

The default groups are:
{your-username} adm cdrom sudo dip plugdev lpadmin sambashare, I think.

[DoYouKubuntu]

The default groups are:
{your-username} adm cdrom sudo dip plugdev lpadmin sambashare, I think.

For my own information, where are you getting those? I'm asking because my /etc/group file has a LOT more groups than that (excluding users). If I used my file (minus my users) to help someone restore theirs, would that work?

I know this sounds like a total noob question, but at this point I can't worry about that. As a famous idiot once said, "It is what it is!"

[claydoh]

For my own information, where are you getting those? I'm asking because my /etc/group file has a LOT more groups than that (excluding users). If I used my file (minus my users) to help someone restore theirs, would that work?

I know this sounds like a total noob question, but at this point I can't worry about that. As a famous idiot once said, "It is what it is!"

web searches verifying output on my systems and virtual machines:

$ groups
claydoh adm cdrom sudo dip plugdev lpadmin libvirt sambashare

I know that here in my case, libvirt is specific to virt-manager/qemu/etc I have installed, so I left this out. Which then matches my mostly stock laptop output.

Also:
cat /etc/group | grep $USER produces the same result:

$ cat /etc/group | grep $USER
adm:x:4:syslog,claydoh
cdrom:x:24:claydoh
sudo:x:27:claydoh
dip:x:30:claydoh
plugdev:x:46:claydoh
lpadmin:x:120:claydoh
sambashare:x:1000:claydoh
claydoh:x:1001:
libvirt:x:132:claydoh

Just because the list of groups is large, it does not mean that the $USER is part of all of those, directly.

[DoYouKubuntu]

Just because the list of groups is large, it does not mean that the $USER is part of all of those, directly.

Yep, you're right. And I wasn't thinking about that at all.

My output is almost identical to yours, @claydoh.