Still seeing this request quite frequently in my website logs, I thought I'd expand the topic a bit more, given the fact that I've somehow left out the most obvious way to Confirm the group Membership for a Ubuntu user.
Group membership in Ubuntu
Every Unix-like OS is bound to have a group command, which is aimed to help you confirm Unix group membership for any user known to your system.
The easiest it to run it and specify a username in command line. The result is a list of Ubuntu groups:
groups greys
greys : admin www-data
If you're looking at confirming the membership for a few users, you can specify usernames in the same command line:
groups greys root
greys : admin www-data
root : root
Resources: unixtutorial
