There’s bunch of instruction talking about how to reset password on raspbian. But they all require physical access to the raspberry pi and take out the SD card and need keyboard and monitor the reset the password.
My case is I forgot my password of course. There’s many reasons: The system is seldomly used. Forgot to put the password into password manager app. The login credential is remembered in SSH client. However, because the credential is kept in SSH client which means I can still log into the raspbian, only thing is I don’t know the password now, and no way to change it.
I tried all possible ‘dictionary attack’ to my pi but no success. Then at the last resort, I figured out something works.