As a member of sudo can I add myself to a group I don't belong to?
$ getent group thegroupname
thegroupname:x:123794798:administrator,users,auser,moreusers,manymoreusers
$ sudo usermod -a -G thegroupname myusername
usermod: group 'thegroupname' does not exist
When I run the above I can't add myself to the group. The error message says the group doesn't exist, but it does.
Here I'll make a new group as per @terdon's comment.
$ sudo groupadd testgroup
useradd: user 'myusername' already exists
$ groups
myusername sudo users
$ getent group testgroup
testgroup:x:01234:
$ sudo usermod -a -G testgroup myusername
$ groups myusername
myusername : myusername sudo users testgroup
Sorry for the typo with just using groups instead of groups myusername. I'm not sure if that information is helpful as it still shows me as not belonging to the test group while groups myusername does.
$ groups
myusername sudo users