postrm is in postgresql-common 173.
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 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 | #!/bin/sh
set -e
if [ remove = "$1" -o abort-install = "$1" -o disappear = "$1" ]; then
    dpkg-divert --package postgresql-common --remove --rename --divert /usr/bin/pg_config.libpq-dev /usr/bin/pg_config
fi
if [ "$1" = purge ]; then
    # remove socket directory
    rm -rf /var/run/postgresql
    # remove SSL keys
    rm -rf /etc/postgresql-common/root.crt 
    [ -d /etc/postgresql-common ] && rmdir --ignore-fail-on-non-empty /etc/postgresql-common || true
    rm -rf /var/cache/postgresql
    # unregister and remove files maintained by ucf
    LRCONFIG="/etc/logrotate.d/postgresql-common"
    CCCONFIG="/etc/postgresql-common/createcluster.conf"
    if which ucf >/dev/null; then
	ucf --purge $LRCONFIG
	ucf --purge $CCCONFIG
    fi
    if which ucfr >/dev/null; then
	ucfr --purge postgresql-common $LRCONFIG
	ucfr --purge postgresql-common $CCCONFIG
    fi
    rm -f $LRCONFIG $LRCONFIG.ucf-* $CCCONFIG $CCCONFIG.ucf-*
fi
# Automatically added by dh_installinit
if [ "$1" = "purge" ] ; then
	update-rc.d postgresql remove >/dev/null
fi
# In case this system is running systemd, we make systemd reload the unit files
# to pick up changes.
if [ -d /run/systemd/system ] ; then
	systemctl --system daemon-reload >/dev/null || true
fi
# End automatically added section
# Automatically added by dh_systemd_enable
if [ "$1" = "remove" ]; then
	if [ -x "/usr/bin/deb-systemd-helper" ]; then
		deb-systemd-helper mask postgresql.service >/dev/null
	fi
fi
if [ "$1" = "purge" ]; then
	if [ -x "/usr/bin/deb-systemd-helper" ]; then
		deb-systemd-helper purge postgresql.service >/dev/null
		deb-systemd-helper unmask postgresql.service >/dev/null
	fi
fi
# End automatically added section
# Automatically added by dh_installdebconf
if [ "$1" = purge ] && [ -e /usr/share/debconf/confmodule ]; then
	. /usr/share/debconf/confmodule
	db_purge
fi
# End automatically added section
 |