How to: OpenBSD reset root password

Posted on in Categories OpenBSD, Sys admin, Tips last updated September 19, 2007

If you forgot your root password, you can simply reset it. The general procedure for resetting password is as follows (if you are a Linux user, see how to reset Linux root password):

a) At boot> prompt force openbsd to boot into a single user mode

b) Next mount file system in read-write mode

c) Run passwd command

d) Sync file system

e) Reboot and login normally.

Procedure to reset root password

At boot> prompt type boot -s to boot into single user mode:
boot> boot -s
Next you will see a message as follows:

Enter pathname of shell or RETURN for sh:

Just hit [Enter] key to load sh shell.
Next mount / and /usr file system in read-write mode:
# mount -uw /
# mount /usr

Finally set or change the password for root user, enter:
# passwd
Press CTRL+D to boot into multiuser mode or just reboot server:
# reboot

Further reading

HowTo: Recovering Linux Grub Boot Loader Password

Posted on in Categories CentOS, Debian Linux, Howto, Linux, RedHat/Fedora Linux, Suse Linux, Sys admin, Tips, Troubleshooting, Ubuntu Linux last updated May 7, 2010

If you have, a password protected grub boot loader and you forgot both root and grub password, then you can recover grub-boot loader password using the following method/procedure:

* Use Knoppix cd
* Remove the password from Grub configuration file
* Reboot the system
* Change the root password
* Setup new Grub password if required (optional)

Linux: Recovering Deleted /etc/shadow Password File

Posted on in Categories Data recovery, Howto, Linux, Sys admin, Tips, Troubleshooting last updated June 7, 2012

You may delete a file called /etc/shadow. If you try to boot into a single user mode, system will ask for the maintenance root password. Now imagine this, you do not have a backup of /etc/shadow file. How do you fix such problem in a production environment where time is a critical factor? I will explain how to recover a deleted /etc/shadow file in five easy steps.