Programster's Blog

Tutorials focusing on Linux, programming, and open-source

PostgreSQL

PostgreSQL - Generated Columns

Learn about generated columns in PostgreSQL. These may be referred to as "computed", "calculated" or "virtual" columns in other relational database systems.

Firefox

Firefox - Compact Mode

Enable compact density in Firefox.

DevOps Bitbucket pipelines

Bitbucket Pipeline Cheatsheet

A cheatsheet for Bitbucket pipelines.

Docker Ubuntu install

Ubuntu 22 - Install Docker

Install docker engine on Ubuntu 22.04

KVM cloud-init

Create Ubuntu 22.04 KVM Guest From Cloud Image

Create an Ubuntu 22.04 KVM guest through the use of the cloud image provided by Canonical.

OpenVPN VPN

Debian/Ubuntu - Start OpenVPN Connection

Learn how to start an OpenVPN connection from the CLI in Debian/Ubuntu.

AWS SSO Cognito OIDC

Verifying AWS Cognito OIDC ID Token

Learn how to verify and decode your OIDC ID token from Amazon Cognito.

JWT

Lecture - 100 Percent Stateless with JWT

Learn about JWTs from a lecture Hubert Sablonnière gave in 2016 at Devoxx.

email SpamAssassin

Check Why Email Failed SpamAssassin Check

Find out how to discover why an email went into your spam folder, when you are using SpamAssassin.

networking firewall nftables

Nftables Cheatsheet

A cheatsheet for using nftables.

pfsense

Resolving Port Forwarding Issue With pfSense

Resolving a port forwarding issue with pfSense when one is running a setup behind another NAT.

pfsense

pfSense - Set SSL Certificate

Learn how to set the SSL certificat on pfSense.

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Programster's Blog Ⓒ 2026