User management in Ubuntu

This post describes a multi-user management method that I use in the lab. Since all the users require a root privilege, it is better to have only one group with the root privilege.

Adding group and user

• Add a group (if the group does not exist.)

  $ sudo groupadd --gid 2000 cglab
  

Giving sudo privilege to a group

• Add a sudo group for allowing the root privilege for those who are in the group cglab.

  $ sudo visudo
    
  # add the following line:
  cglab ALL=(ALL) ALL
  

• Add a user and assign the user to group(s).

  $ sudo useradd USER_NAME -m
  $ sudo passwd USER_NAME
  $ sudo usermod -aG cglab,docker USER_NAME
  

  • Tip.
    • -m: Create a home directory.
    • -a: Add a user to the supplementary group(s).
    • -G: A list of supplementary groups in which the user is associated.
• In the user account, type the following to set the primary group:

  $ sudo usermod -g cglab USER_NAME
  

  Tip. -g: sets a primary group

---

• Note: Adding a user to groups
  • If you are running a NIS server, add the user to groups in the master server, as well as the client server. e.g.,:

    # using the new user account in the client server,
    $ sudo usermod -aG cglab,docker USER_NAME
    

• Note: Changing shell
  • Make sure to install zsh and oh-my-zsh first

    $ sudo apt-get install zsh
    $ sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"
    

  • If you are running NIS server, the following code should be done in the master or slave server. Otherwise, do this in the local server:

    $ sudo vim /etc/passwd
    
    # add following at the end of the line where USER_NAME is:
    /bin/zsh