debconf-set on ubiquity

[Daniel Manrique]

Hi folks!

Hopefully some of the knowledgeable folks here may shed a bit of light on a
problem I'm having.

I'm using a preseed file which has this bit of logic to try to determine the
hard disk to install to:

d-i partman/early_command string \
        wwn_disk_path=$(ls -1 /dev/disk/by-id/wwn* | head -n 1); \
        if /usr/bin/test "$wwn_disk_path" == "" ; then \
                debconf-set partman-auto/disk /dev/sda ; \
        else \
                debconf-set partman-auto/disk string /dev/$(udevadm info
--query=name --name=$wwn_disk_path ); \
        fi; \
        true;

This works just fine on d-i (server and alternate installations), but on desktop
installations (Ubiquity), I get:

ubuntu log-output: sh: 1: debconf-set: not found

Is there an equivalent that will work with Ubiquity?

I tried using

echo  "d-i partman-auto/disk string /dev/sda" |debconf-set-selections

but it still doesn't do what I want (namely, to set partman-auto/disk to
something, so that when I try to install on a system with one HD and one USB
stick plugged in at install time, it doesn't prompt me about what to do). It
fails with an error about /var/cache/debconf/config.dat being locked by another
process.

Thanks in advance!

- Daniel