postrm is in maas-dns 1.5.4+bzr2294-0ubuntu1.2.
This file is a maintainer script. It is executed when installing (*inst) or removing (*rm) the package.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | #!/bin/sh
set -e
if [ "$1" = "remove" ]; then
	if [ -f /etc/bind/named.conf.local ]; then
		sed -i '/^include.*\"\/etc\/bind\/maas\/named.conf.maas\"\;$/d' \
			/etc/bind/named.conf.local
	fi
fi
if [ "$1" = "purge" ]; then
	# Remove zone files
	if [ -d /etc/bind/maas ]; then
		rm -rf /etc/bind/maas
        fi
fi
if [ -x /usr/sbin/invoke-rc.d ]; then
	invoke-rc.d bind9 restart || true
fi
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