Although the script is running with -e, having two distinct invocations
of a subshell in the same instruction masks failures in the first
subshell invocation. It is similar in essence to what the pipefail
option controls.
As a consequence, the following instruction does not fail if distro-info
is not installed:
isoname=$(distro-info -d)-live-server-$(dpkg --print-architecture).iso
And therefore, we end up with something like:
isoname=-live-server-amd64.iso
Fixed by first assigning the value of $(distro-info -d) to a variable.
Signed-off-by: Olivier Gayot <olivier.gayot@canonical.com>