Checklists for software errors, setup, and tool workflows.

How to Fix Git Detached HEAD State and Undo Changes

You run git status and see something like "HEAD detached at abc123". This ha...

Fix 'package.json Not Found' After Cloning a Repository

Symptom

You clone a repository from GitHub (or another remote), change into the directory...

Docker Container Exits Immediately with Exit Code 137

You start a Docker container, and it exits almost immediately with exit code 137. This usually me...

Fix Nginx 502 Bad Gateway with Docker and PHP-FPM

You have a Docker setup with Nginx proxying to a PHP-FPM container, and you're getting a 502 ...

Fix Python venv Not Activating in VS Code Terminal

When you create a Python virtual environment but it doesn't activate in the VS Code terminal,...

Fix Cloudflare Wildcard Subdomain Not Resolving

You set up a wildcard DNS record in Cloudflare (e.g., *.example.com) expecting all s...