postinst is in menu 2.1.46ubuntu1.
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
# Package maintainers, DO NOT use this as an example for how to
# call update-menus in your postinst! This script does several things
# you shouldn't do, and doesn't do other things that you should
# do. See /usr/share/doc/menu/ for more info.
case "$1" in
triggered)
	# This is triggered by any installation of a menu file and by
	# any call to update-menus made in a package maintainer script.
        test -x /usr/bin/update-menus && update-menus --trigger
        exit 0
;;
*)
	chmod a+x /usr/bin/update-menus
	update-menus
;;
esac
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