Git is a powerful tool. Once you’ve mastered `commit` and `merge`, there are endless possibilities. A very useful one is `[git-bisect](https://git-scm.com/docs/git-bisect)`. It helps you find a commit that introduced a certain change in behavior.

We use `git-bisect` a lot in the [Node.js project](https://github.com/nodejs/node). The Node.js project has good continuous integration but some bugs are only discovered after a release. With `git-bisect`, it’s easy to find the bad commit.

#### Try it!

If you want to try out `git-bisect`, here is a [demo repository](https://github.com/fhinkel/git-bisect-demo). At some point, a bug was introduced as you can see by running `npx mocha test1.js`. Can you find the bad commit?

![](https://hackernoon.com/hn-images/1*wqy1LNZewAp5t7FXFCiiwA.png)

[Use this repository to practice git bisect.](https://github.com/fhinkel/git-bisect-demo)

#### Automating git-bisect

Instead of testing each step manually, you can run `git-bisect` with a script. It will use the script at each step and automatically mark the commit, until it finds the **first bad commit**.

![](https://i.ytimg.com/vi/pFavI1XgxYs/hqdefault.jpg)

Understanding Git-Bisect, i.e. Use Binary Search to Find the Change that Introduced a Bug

Too Long; Didn't Read

@fhinkel

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