User accounts
Groups
Add a new group
$ sudo addgroup webdev
or
$ sudo groupadd webdev
Delete a group
$ sudo delgroup webdev
or
$ sudo groupdel webdev
Add a user to a group
$ sudo adduser username groupname
or
$ sudo useradd -G groupname username // for a new user
or
$ sudo usermod -a -G groupname username // for an existing user
List a user's groups
$ id -Gn username
Check a user's primary group
$ getent group username
Change a user's primary group
$ sudo usermod -g groupname username
Check user's group assignments
$ id username
or
$ groups username
or
$ id -Gn username
Set a directory writable by a certain group
Make /srv/www folder readable/writable/executable by dev group
$ sudo setfacl -d -m g:dev:rwx /srv/www
Add a user account
$ sudo useradd -d /home/jsmith -m jsmith -G webdev
$ sudo passwd jsmith
Delete a user account
Force removal and delete files
$ sudo userdel -fr username
or
$ sudo deluser -remove-home username
Lock or unlock a user account
$ sudo passwd -l username
$ sudo passwd -u username
Adding sudoers
A file can be added for groups of users or specific users to /etc/sudoers.d/ directory. This line would make someone a sudoer with no password requirement.
jsmith ALL=(ALL) NOPASSWD:ALLIf you want the user to type a password.
jsmith ALL=(ALL:ALL) ALLUpdating sudoers file safely
- Last checked on Ubuntu 16.04.01 LTS (xenial)
The command visudo checks the validity of the sudoers file before making the actual update to the file, and this is the recommended way of editing the file because one can potentially lose sudo privileges unintentionally.
$ sudo visudo
Instead editing /etc/sudoers file I usually create a file at /etc/sudoers.d/localusers so I edit that instead.
$ sudo visudo -f /etc/sudoers.d/localusers
Changing the default editor used for visudo
I'm a VIM user, but many of the distros default to nano for newcomers to Linux systems. You can use the following command to change the default editor that is loaded for visudo and for many other apps.
$ sudo update-alternatives --config editor