Linux user and group management
$ cat /etc/group
group name:password:group id:group users
groups
: show groups to which current user belong to
groupmod
: modify a group
groupadd
: create a new group
groupdel
: delete an existing group
gpasswd
-d user2 web
users
: show logged in users
usermod
: modify user account
usermod -aG group user
, add user user into group group
useradd
: add a user account
useradd -m -c "comment" -s /path/to/shell -G group_list user_name
-m
create home
userdel
: delete a user account