Lost all passwords?

You wake up after second successful installation of Linux and remember only three packs of beer and no passwords at all?

If your computer boots, you can set new passwords. When in LILO type

boot: init=/sbin/init -s
or
boot: init=/sbin/init -1

It will pass option to the kernel and the system will boot into single user mode or else called maintaince mode and give you root privileges without asking any passwords. Type

# passwd root

and set new password for the root user (you'll set other passwords later). Then type

# reboot

and wait while your system reboots. Do not do anything else in single mode - you can seriously damage your system in this mode. When booted, login as root and using the same command

# passwd user_name_here

change passwords for the other users you've created. A list of them can be retrieved by typing:

#cat /etc/passwd

Continue working/exploring/playing.

Linux does not have amnesia ;)