This morning I booted up the PinguyOS linux installed on my VirtualBox (on Windows). I stucked at login page because I do not remember the password. I searched for how to reset pinguyOS linux and ubuntu linux. I found two methods, one method using boot into root bash through recovery boot and the other method directly boot into root bash. First method didn’t work for me as root bash asked for me the password and I don’t know root password. Second method didn’t directly work as well. That article said ‘find line starting with kernel’ and I couldn’t find that one. I figured out and tried the following and I did reset my password.