Что такое системы контроля версий (VCS)?

Imagine: yesterday the code worked; today, after edits, everything broke. Without a version control system (VCS) you would have to copy the project folder by hand and name it project_final_v2_LAST. A VCS solves three things at once: it records who changed what and when, lets you compare any two versions line by line, and lets you roll back to any previous state. In this chapter you will go from the idea of VCS all the way to practice — installing Git, creating repositories, the file lifecycle, viewing history, and .gitignore.

Git doesn't store files linearly — it stores a graph of commits. Each commit points to its parent(s). Branches are just named pointers to commits. When you create a feature branch, merge it back, and tag a release, you get a graph like this. Click any commit to see its details.

Git was created in 2005 by Linus Torvalds to manage the Linux kernel source code — a project with thousands of contributors and decades of history. The design priorities were: speed, data integrity, and support for distributed non-linear workflows (many branches). Today Git is the de facto standard for version control: nearly all open-source projects, and most companies, use it.