Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

You've updated your DNS records at Cloudflare, but hours later the changes still aren't s...

You're about to install or update a package, and you see warnings like "requires Node.js ...

You try to write a file inside a running Docker container and get no space left on device

Fixing pip Externally-Managed Environment Errors
If you see the error error: externally-managed-environment when running pip in...

Fixing Nginx Upstream Connection Refused on Port 443
You see "upstream connection refused" in your Nginx error log when proxying requests to p...

How to Fix a Detached HEAD with Git Reset --hard
You're working in Git, and suddenly you see a warning: You are in 'detached HEAD...