Users

Courtesy of cyberciti.biz

Introduction: By default, the cloud server comes with a user named ubuntu. You can use such primary user account for sysadmin tasks on Ubuntu. However, sometimes you need to add a user account on Ubuntu for additional sysadmin tasks. This page shows how to create a regular user account or sysadmin account on the Ubuntu server.

Add User

Steps to create a user account on Ubuntu Linux 1. Open the terminal application
2. Log in to remote box by running the ssh user@your-ubuntu-box-ip
3. To add a new user in Ubuntu run sudo adduser userNameHere 4. Enter password and other needed info to create a user account on Ubuntu server
5. New username would be added to /etc/passwd file, and encrypted password stored in the /etc/shadow file

Example

bbearce@bbearce-XPS-15-9560:~$ sudo adduser vivek
[sudo] password for bbearce: 
Adding user `vivek' ...
Adding new group `vivek' (1001) ...
Adding new user `vivek' (1001) with group `vivek' ...
Creating home directory `/home/vivek' ...
Copying files from `/etc/skel' ...
Enter new UNIX password: 
Retype new UNIX password: 
passwd: password updated successfully
Changing the user information for vivek
Enter the new value, or press ENTER for the default
    Full Name []: 
    Room Number []: 
    Work Phone []: 
    Home Phone []: 
    Other []: 
Is the information correct? [Y/n] y

Verification

Use the grep command or cat command as follows:

$ cat /etc/passwd
.
.
.
vivek:x:1001:1001:,,,:/home/vivek:/bin/bash

or

$ grep '^vivek' /etc/passwd
vivek:x:1001:1001:,,,:/home/vivek:/bin/bash

Check group, groupid and userid of user:

Use id:

$ id <user>

Ex:

bbearce@bbearce-XPS-15-9560:~$ id bbearce
uid=1000(bbearce) gid=1000(bbearce) groups=1000(bbearce),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),113(lpadmin),128(sambashare),130(docker),999(microk8s)

Delete User

Remove the user

1. Log in to your server via SSH.
2. Switch to the root user:
   $ sudo su -
3. Use the userdel command to remove the old user:
   $ userdel <user's username>
4. Optional: You can also delete that user's home directory and mail spool by using the -r flag with the command:
   $ userdel -r user's username

Warning: Only delete a user's home directory if you are certain you no longer need their files or mail.

Change Password

Source: cyberciti

Type following passwd command to change your own password: $ passwd

Sample Outputs:

Changing password for vivek
(current) UNIX password:
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

Add User to Sudo

Source phoenixnap

usermod –aG sudo newuser