prerm is in nagios3-cgi 3.5.1-1ubuntu1.
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 | #!/bin/sh -e
. /usr/share/nagios3/debian/httpd.webapps-common
apacheconf="/etc/nagios3/apache2.conf"
if [ -f $apacheconf ]; then
  case "$1" in
    remove)
	# find the configured servers
	configured_servers=`wc_httpd_apache_configured $apacheconf nagios3`
	if [ "$configured_servers" ]; then
		# deconfigure them
		wc_httpd_apache_uninclude $apacheconf nagios3 $configured_servers
		# reload the configured servers if they are running 
		running_servers="`wc_httpd_running $configured_servers`"
		if [ "$running_servers" ]; then
			wc_httpd_invoke "reload" $running_servers
		fi
	fi
      ;;
  esac
fi
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