Comment 0 for bug 1689944

Recent core snap images (edge channel revision 1886) do not contain the previously known files used to detect that a system is ubuntu core.

In this bug, we should collect as many known paths/files/commands so we're hopefully defensive against further changes.

Ubuntu Core 16
--------------
% cat etc/os-release
NAME="Ubuntu Core"
VERSION="16"
ID=ubuntu-core
PRETTY_NAME="Ubuntu Core 16"
VERSION_ID="16"
HOME_URL="http://www.snapcraft.io/"
BUG_REPORT_URL="http://bugs.launchpad.net/snappy/"

% snap version
snap 2.24+201704201952.git.2ba71ec~ubuntu16.04.1
snapd 2.24+201704201952.git.2ba71ec~ubuntu16.04.1
series 16
kernel 4.4.0-59-generic

% lsb_release -rd
bash: lsb_release: command not found

% test -e /writable/system-data/var/lib/snapd; echo $?
0

Ubuntu 16.04 (Classic)
-----------------------
 % cat /etc/os-release
NAME="Ubuntu"
VERSION="16.04.2 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.2 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial

% snap version
snap unknown
snapd 2.24.1
series 16
ubuntu 16.04
kernel 4.4.0-75-generic

% lsb_release -rd
Description: Ubuntu 16.04.2 LTS
Release: 16.04

% test -e /writable/system-data/var/lib/snapd; echo $?
1