Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

If Git operations suddenly fail with an error like fatal: Unable to create 'path/.git/i...

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

Fix pip Externally Managed Environment Error on Linux
If you're seeing error: externally-managed-environment when trying to pip ...

Fix npm run build Failed with PostCSS Error
You run npm run build and see a PostCSS error. This often happens after updating pac...

Fix VS Code 'Cannot Save File: Permission Denied' on Mac
You're editing a file in VS Code on your Mac, hit save, and get: 'Failed to save:...

How to Recover from a Detached HEAD in Git After a Rebase
You're in the middle of a rebase, you see a message like 'detached HEAD', and you'...