How do you remove configuration settings from debconf

Question

I've tried this approach mentioned in many places, but it fails with the following error message:

sudo echo PURGE | debconf-communicate mirrorsync debconf: DbDriver "passwords" warning: could not open /var/cache/debconf/passwords.dat: Permission denied 0

Answer 1

I suspect that the problem is that sudo is no longer effective after the pipe character so the subsequent command is not as root.

See Pipe command with sudo and factor sudo across pipes.