De su sitio web:
BunsenLabs Linux is a distribution offering a light-weight and easily customizable Openbox desktop. The project is a community continuation of CrunchBang Linux.
The current release is Helium, derived from Debian 9 (Stretch).
(...)
The distribution consists of configuration and resource packages installed on top of Debian. There are no changes to the way the Debian base system is administrated.
Entonces, sí, puede instalar cualquier paquete Debian en él, siempre que defina los repositorios correctos.
Вам нужен Zenity:
sudo apt-get install zenity
Затем, чтобы получить пароль, выполните:
#!/bin/bash
echo "Some Code..."
read Input < <(zenity --password --title="Enter your password")
if [[ "$Input" = "password" ]]; then
echo "Do something"
fi