This brief guide explains how to reset sudo password in Ubuntu 20.04 LTS desktop or server editions. When installing Ubuntu for the first time, a new sudo user will be created to perform all sorts of administrative tasks. If you have more than one sudo users, you can easily reset the forgotten sudo user or administrative user password from another sudo user account. What If you have only one sudo user and you lost the password? No problem! It is very easy to recover forgotten sudo user password in Ubuntu. I tested this guide on Ubuntu 20.04 LTS server, however the steps given below are same for other Ubuntu versions and derivatives.
Reset Sudo Password In Ubuntu 20.04 LTS
We can reset the users' password from the "rescue" or "single user" mode. To reset a sudo user's password, first you need to ENTER into rescue mode. Refer the following guide to boot into rescue mode in Ubuntu-like systems.
After you entered in to the rescue mode, mount the root (/) file system in read/write mode by entering the following command:
# mount -n -o remount,rw /
Now, reset the sudo user's password using "passwd" command:
# passwd sk
Here, "sk" is the sudo user. Replace it with your own user name.
Enter the password twice:
New password: Retype new password: passwd: password updated successfully
That's it. We have reset the sudo user password. If you have followed the Method 1 to enter into rescue mode as described in the above link, press “Ctrl+d” to boot into normal mode. Alternatively, you can type any one of the following commands to boot into normal mode.
If you want to reboot the system instead of booting into normal mode, enter:
If you have followed the Method 2 to enter into rescue mode as described in the above link, type:
You will go back to the recovery menu. Choose "Resume normal boot" and hit ENTER key.
Again, choose OK and press ENTER to continue booting into normal mode:
You can now use the new sudo password when running administrative commands.
What if I forgot both username and password?
If you forget the username, you can easily list the available users in your Linux system using command:
# cat /etc/passwd
Sample output from my Ubuntu 20.04 system:
[...] sk:x:1000:1000:sk,,,:/home/sk:/bin/bash [...]
Well, you now have the user name. Just follow the aforementioned steps to reset the user's password.
Hope this helps.