postinst is in nfs-kernel-server 1:1.3.4-2.1ubuntu5.
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 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50  | #!/bin/sh
set -e
# Automatically added by dh_systemd_enable/11.1.2ubuntu1
# This will only remove masks created by d-s-h on package removal.
deb-systemd-helper unmask 'nfs-server.service' >/dev/null || true
# was-enabled defaults to true, so new installations run enable.
if deb-systemd-helper --quiet was-enabled 'nfs-server.service'; then
	# Enables the unit on first installation, creates new
	# symlinks on upgrades if the unit file has changed.
	deb-systemd-helper enable 'nfs-server.service' >/dev/null || true
else
	# Update the statefile to add new symlinks (if any), which need to be
	# cleaned up on purge. Also remove old symlinks.
	deb-systemd-helper update-state 'nfs-server.service' >/dev/null || true
fi
# End automatically added section
# Automatically added by dh_systemd_start/11.1.2ubuntu1
if [ -d /run/systemd/system ]; then
	systemctl --system daemon-reload >/dev/null || true
	if [ -n "$2" ]; then
		_dh_action=restart
	else
		_dh_action=start
	fi
	deb-systemd-invoke $_dh_action 'nfs-server.service' >/dev/null || true
fi
# End automatically added section
case "$1" in
    configure)
	ucf --three-way /usr/share/nfs-kernel-server/conffiles/etc.exports /etc/exports
	ucf --three-way /usr/share/nfs-kernel-server/conffiles/nfs-kernel-server.default /etc/default/nfs-kernel-server
	for f in /var/lib/nfs/etab  \
		 /var/lib/nfs/rmtab \
		 /var/lib/nfs/xtab; do
	    [ -e $f ] || touch $f
	done
	update-rc.d nfs-kernel-server defaults 20 80 >/dev/null
    ;;
esac
act="restart"
[ "$1:$2" = "configure:" ] && act="start"
invoke-rc.d nfs-kernel-server $act || echo "Failed to ${act} nfs-kernel-server, ignoring."
 |