Sometimes as an IT Administrator you are requested to reset a user password. Here is how I did it:
1. Boot grub and choose recovery mode and do not press enter.
2. Press “e” key, go to the end of line “linux /boot/vmlinuz-…” and add a space (press spacebar once) and type “init=/bin/bash” and press “Ctrl-x” to boot.
3. After finished booting, type “mount -rw -o remount /” and press enter.
4. Type “passwd <username>” and press enter. Replace <username> with the real username whose his/her password needs to be resetted.
5. Type in a new password and press enter.
6. Type in the same password for confirmation and press enter.
7. Type “reboot”.
8. That’s it!