users and groups of linux

● add a user (新增使用者)

sudo useradd name

或是

sudo adduser name

 
範例:

sudo adduser --system --no-create-home --group yourusername

The –system flag (-r) will create a system user – one which does not have a password, a home dir and is unable to login.
Q 1st: –no-create-home is no need?
Q 2nd: –group is for what?
 

● modify the username of a user:

sudo usermod -l new_username old_username

● To change the password for a user:

sudo passwd username

● change the shell for a user:

sudo chsh username

● To change the details for a user (for example real name):

sudo chfn username

● remove/delete a user

sudo userdel username

 
Then to delete the home directory for the deleted user account:

sudo rm -r /home/username

 
Bonus: If you want to delete user’s home directory/mails as well

sudo deluser --remove-home username

and

sudo deluser --remove-all-files username

will remove the user and all files owned by this user on the whole system.
 

● list all the groups

cat /etc/group

● list all the groups of which the current user is a member

groups

● list the members of a group

getent group groupname

● add a user to a specific group use

sudo usermod -G groupname -a username

● remove a user from a specific group

sudo gpasswd -d username groupname

● delete a group

sudo groupdel groupname

 
#linux #user #adduser #removeuser #group #addgroup #removegroup

2015/3/15