Sometimes it is necessary to get root access, for example when you have forgotten your password or changed something in /etc/sudoers and things do not work as expected.
Be careful, because this step will give you full root access to your system and you can really damage your system! Keep in mind that all the steps you see here can also be done by someone else!
Now let us start with a way that should work on any freshly installed Ubuntu system:
The Standard Way
This procedure gives you a full root shell! You can damage your system if you are not careful!
When booting up press SHIFT (in systems 9.10 "karmic" or later) or ESC (in systems 9.04 "jaunty" or earlier) at the grub prompt and use the arrow keys to select the rescue mode option and press enter.
- The file system may be read only (it is in all currently supported releases). Remount as read write
mount -rw -o remount /
- This will boot the system in rescue mode and you should arrive at a prompt that looks like this
- To reset your password type this in
passwd <username>Press return, then you will be prompted to enter and confirm a new password.
- Once you are done resetting your password you can than switch back to the normal GUI mode by putting this in
If if appears to boot normally, but you see a message that says:
- Give root password for maintenance (or type Control-D to continue):
then you will have to try a different trick below.
The Other Way
If the "Standard Way" does not work for you and you recieve the "Give root password for maintenance" message, you can recover your password using the following steps
1. Reboot your computer
2. Press SHIFT or ESC at the grub prompt (as earlier).
3. Select your image.
4. Highlight the line that begins kernel and press 'e' to edit
5. Go to the very end of the line, change the ro to rw and add init=/bin/bash
press enter, then press b to boot your system.
Your system will boot up to a passwordless root shell.
6. Type in passwd username
7. Set your password.
8. Type in reboot
The Other Way Lucid
At least for 'Lucid' I found out that the steps 1-5 in the procedure mentioned above are slightly different:
1. Reboot your computer
2. Hold shift during boot to start GRUB menu
3. Highlight your image and press 'e' to edit
4. Find the line starting with linux and append init=/bin/bash at the end of that line
5. Press ctrl-x to boot.
Then follow the steps 6-8 as mentioned above.