Creating Users in Linux and Enabling Graphical Login

Many Linux beginners encounter a problem after creating a new user: they can switch to the user in a terminal but cannot log in to the graphical desktop. This usually happens because the user is created without a proper home directory or sufficient permissions for the display manager.

Environment Preparation

First, gain root privileges (temporarily) with:

sudo su root

Creating the User Correctly

The command pair:

useradd testname
passwd testname

only creates a basic user entry. To allow graphical login, the user needs a home directory and the correct ownership.

Recommended User Creation Commands

1. Create a user with a home directory:

useradd -d /home/testname -m testname

• -d /home/testname specifies the home directory path.
• -m ensures the directory is created if it does not exist.

2. (Optional) Add the user to the root group immediately:

useradd -d /home/testname -m testname -g root

Verify the User's Groups

groups testname

Completely Remove a User (if needed)

userdel -r testname   # -r removes the home directory as well

Setting the Password

passwd testname

Enter the new passwodr twice. Note that the input will not be echoed for security reasons.

Granting sudo Access (Optional but Recommended)

Even if the user is in the root group, they may not have sudo privileges. To enable sudo:

sudo su root
visudo   # or vim /etc/sudoers

Look for the line:

root    ALL=(ALL:ALL) ALL

Add a new line below it:

testname    ALL=(ALL:ALL) ALL

Save and exit (:wq! in vim).

Logging In

After completing these steps, log out of your current session (or restart the display manager) and try logging in with the new user account. You should now see the graphical desktop.

Troubleshooting Tips

• Ensure the home directory exists and is owned by the user:

chown -R testname:testname /home/testname

• If the display manager still refuses login, check /var/log/lightdm.log or /var/log/gdm3/ for specific errors.
• Always use useradd with -m when creating users intended for interactive use.