The root user is nothing but the default user created in Linux system with administrative privileges. Similar to older Ubuntu versions, the root user is locked in Ubuntu 20.04, and a user can never log in as root initially. The system of using the command sudo is used instead, which allows any non-administrative user to perform administrative tasks like installation, without actually logging in as root, but with root privileges.

However, there can be certain crucial administrative tasks which are not allowed with the sudo command and can only be performed when root user is logged in. There are ways to set or reset the root password in such scenarios. Note that, this should be used only in such cases where the command sudo is incompetent, as logging in as root user possesses a security risk for your computer.

Set/Reset Root Password

This step requires that you are logged in as a user with sudo privileges and the command su is allowed as part of sudo privileges.

Run the following to login as root. Enter your password when prompted.

sudo su

As seen above, the prompt has now changed to root. Thus we are able to login to root using our own password.

Now, to change the root password, simply use the command passwd.

passwd

This will set the root password when used for first time, or change it to the new password when used afterwards.

Time to check if the new password works. Press Ctrl + D to exit root prompt. Then type command su to login as root, and enter the new root password which we just set.

su

In this way, we have successfully modified the root password and able to log in as root.

However, as said before, this requires your own user to have sudo access. But what if you don’t have sudo access but still need to change the root password in case of an emergency? Is there a way to log in as root in such a case? Let’s find out.

Reset Root Password from Grub

There is a way to change the password of root or of any other user for that matter while booting into Ubuntu. It needs a little bit of tweaking the boot process.

First, restart your computer. If the GRUB menu doesn’t automatically appear for you every time while booting, hold the Shift key while booting. This will forcefully show the GRUB menu.

Next, mark the line Ubuntu from the menu and press e to edit the boot configuration.

We need to do the modification on the line starting with linux, which is the second last line in the configuration. Replace the last part quiet splash with rw init=/bin/bash.

Basically the change we are doing here is to login to a shell (init=/bin/bash) instead of GUI (quiet splash) with read and write (rw) privileges.

Press F10 to boot with this configuration. Note that this changed configuration is used only for that boot and is reset on the next boot.

As you can see, we are logged in as the root user on the shell prompt.

Now, as done previously, we can run the command passwd here and reset the root password.

passwd

The root password has been changed. Now reboot the system normally and login as root with the new password.

You can now perform the required administrative tasks.

Conclusion

We saw two ways of changing the root password in Ubuntu 20.04. Note that wherever possible, sudo command must be used to perform administrative tasks. Logging in as su should be prevented as much as possible, as it can compromise the security of the system, especially if it is connected to a network.