#!/bin/bash

set -e

# Define errors and exit codes
E_NO_DEBIAN=1
E_MSGS[$E_NO_DEBIAN]="No debian-based distribution"

function safe_exit () {
	local CODE="$1"
	MSG=${E_MSGS[$CODE]}
	if [ -z "$MSG" ]; then
		cat <<-EOF
		Undefined exit message.

		Please inform $(basename $0) developer to update his program to
		use error codes
		EOF
	else
		echo $MSG
	fi
		
	exit $CODE
}

if [ ! -e /etc/debian_version ]; then
	safe_exit $E_NO_DEBIAN
fi

for PKG in $(dpkg --get-selections | grep -E '(install)$' | awk '{print $1}')
do
	[ -z "$(apt-cache show "$PKG" | grep '^Filename: ')" ] && echo "$PKG"
done