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en/appendix_a_project_lifecycle

Ruby Project Lifecycle and Core Tooling ️

Why this appendix exists 💡

A student can understand Ruby syntax and still feel lost when working in a real project. The missing knowledge is often not "more language features." It is the operational flow around the language:

This appendix teaches Ruby tools through the story of a real project lifecycle, from "I have an empty directory" to "I am working in repeated sprint cycles with a maintainable codebase."

Main learning outcomes 🎯

By the end of this appendix, students should be able to:

Teaching philosophy 🧭

This appendix does not teach tools as an alphabetical catalog.

It teaches them in the order a real developer tends to need them:

That order matters. When students learn tools in project order, the purpose of each tool becomes obvious.

Files in this appendix 🗂️

What this appendix is not 🚫

It is not:

It is a practical survival guide for students moving from "I can write Ruby" to "I can work inside a Ruby project responsibly."

The Ruby Project Lifecycle Story

Stage 0: Before the project exists 🌅

Before a Ruby project has code, it already has one invisible dependency: the Ruby interpreter itself.

If the wrong Ruby version is active, every later step becomes unstable:

This is why project lifecycle starts with the runtime, not with source files.

ruby - v which ruby rbenv versions rbenv local 3 . 4 . 8 rbenv which ruby story.md bash What each command tells you ruby -v

which ruby