Mar 14 2017
i see a note at some web site and i started testing,
but first make a new setup anyway
and as part of the procedure change the password of user pi.
But first i make a note of the user pi password setting:
sudo cat /etc/shadow
is the (a) password raspberry hash.
with sudo nano /etc/shadow you can edit that line and change password back to raspberry,
but that's the point: if you locked yourself out! how to do that?
so i just put the SD back in the card reader, put that in the USB of a RPI ( with a running system ) and search for the card reader mount:
cd /media/pi/xxxxxxxxxxxxxxx but not boot xxx/etc/
sudo nano shadow
as i work headless, ! that is so easy only if the boot option is "pi login to desktop"
what includes a auto mount ( of USB drives... ) !
and here the tested SED line:
sudo sed shadow -i -e "/^pi:/s|.*|pi:\$6\$pLTmrmp1\$r5M8L6MKyu/6wyva0h4DSdZzdUnD0FmQF8PWLtKLSAGQ4EE95VsytHkbnyP3aDhh8EMq/Td2APtyyevKp8XSs.:17228:0:99999:7:::|"
note: i needed s||| for separation and \$ for each $ in HASH
want read about that shadow file thing? here
now check for a other way from forum
sudo nano /media/pi/boot/cmdline.txt
add " init=/bin/bash"
i try from TV but could not read all terminal window, several linux commands did not work,
go back to card reader and change back.
next day try again.
i change the /boot/cmdline.txt from remote and sudo reboot ( while TV ON waits for HDMI )
now screen readable
on passwd can type new password / retype password ( ok, not ask for old password )
but get error and password unchanged
and get error failed to read mtab
but anyhow try
mount -o remount,rw /
and get password updated successfully
good, i even tested nano... works also but can not reach /boot/
( there is a /boot/ but empty, the real /boot/ not mounted )
so again, go back card reader