command -v \youtube-dl >/dev/null 2>&1 || { echo >&2 "shell-things contains youtube-dl alias for automatically setting video title as name, so you might want to install youtube-dl."; }

command -v \gtk-redshift >/dev/null 2>&1 || { echo >&2 "xsessionrc tries to start gtk-redshift automatically on boot, so you might want to install it (or redshift in some distributions)."; }

if [ ! -f /usr/share/doc/gnupg-curl/copyright ]
then
    echo "You might want to install gnupg-curl. It allows you to use shortened URLs with gpg1."
fi

if [ ! -f /usr/share/doc/popularity-contest/copyright ]
then
    echo "You might want to install popularity-contest. See http://popcon.debian.org/"
fi