Git

Git is the actual open-source version control software that runs locally on your computer to track file changes. GitHub, on the other hand, is a cloud-based hosting service built around Git that allows developers to collaborate and store their repositories online. You can use Git entirely offline without ever touching GitHub.

To undo a specific commit without rewriting project history, you should use the command `git revert <commit-hash>`. This creates a brand new commit that does the exact opposite of the changes made in the targeted commit. This is the safest method for undoing mistakes in shared, multi-developer repositories.

Git was created in 2005 by Linus Torvalds, the same developer who created the Linux kernel. He developed it specifically to manage the massive source code of the Linux kernel after the community lost free access to a previous proprietary tool. Since then, it has become the absolute global standard for version control.

A merge conflict occurs when two branches modify the same line of code and cannot be merged automatically. You must manually open the conflicted file, look for the conflict markers (`<<<<<<<`, `=======`, `>>>>>>>`), edit the code to your desired state, and then stage the file. Once all conflicts are staged, you can complete the commit.