Password-Protecting Shell Scripts

When setting up systems, configuring applications and making changes I prefer to script things rather than follow instructions. Main drawback of scripting is that it takes more time but has (in my view) a number of advantages

  • Scripting makes things reproducible
  • Allows for checking and validation
  • (when needed) can produce change logs
  • It can be reused when the same change has

However, frequently these scripts contain sensitive information (e.g. passwords) and must be transferred to someone (or another system) so they should not be stored in clear text. This post explains how to encrypt shell scripts using openssl for cross-platform use.

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Multiple Mosquitto instances on Debian with Systemd

I have been playing for quite a while MQTT to have my Arduino devices communicate with Node-Red for all kinds of automation. Due to the constraints of the Arduino’s, so far I have not been able to effectively secure this as SSL/TLS is not an option on these devices.

Mosquitto supports multiple listeners out of the box though aside from the listener-specific settings all listeners share the same global (e.g. authentication and plugin) settings. To secure my setup and to work on a more permanent solution I needed different settings per listener for which multiple Mosquitto instances are required (i.e. multiple instances of the mosquitto daemon with their configuration and listeners different IP addresses / ports). This was not difficult on my Debian server but as I did not find much documentation on this I will document the necessary steps in this post.

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