Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

You're working in Git, and suddenly you see a warning: You are in 'detached HEAD...

Fix Nginx 'Permission Denied' Upstream Errors
When Nginx logs permission denied while connecting to an upstream (e.g., a Unix sock...

Fix Docker Compose Port Already Allocated for PostgreSQL
You run docker-compose up and see an error like "Error starting userland pro...

Fix Node Version Incompatibility When Installing Packages
You try to install an npm package and get an error like Unsupported engine or ...

Fix 'Permission Denied' When Running pip install --user
If you see Permission denied when running pip install --user somepackage

Docker Nginx 502 Bad Gateway: Memory Limit Fix
You're running Nginx in Docker as a reverse proxy, and suddenly you see 502 Bad Gateway error...