Basically, I have a preseed Debian install that runs a postinstall bash script as root on first login. This script should edit sudoers to make passwords optional when any user in the sudo group uses sudo:
sed -i.bak 's/%sudo ALL=(ALL:ALL) ALL/%sudo ALL=(ALL) NOPASSWD:ALL/' /etc/sudoers
However, something seems to have gone wrong and users still require a password to use sudo - long story short this effectively means no one has sudo as all users are created with --disabled-password. Yes, I realize this may not be the ideal/right/smart/secure way but it is what it is.
What I need to figure out is, what went wrong? Why? The script has worked every other time I've used it and it obviously ran other commands such as updating certain packages, so why didn't it properly edit /etc/sudoers? How can I check sudoers without root or otherwise figure out why it failed to edit?