Git from the Bottom Up – The Index


Manage episode 342203022 series 65608
By Allen Underwood, Michael Outlaw, Joe Zack, Allen Underwood, Michael Outlaw, and Joe Zack. Discovered by Player FM and our community — copyright is owned by the publisher, not Player FM, and audio is streamed directly from their servers. Hit the Subscribe button to track updates in Player FM, or paste the feed URL into other podcast apps.

This episode, we learn more about Git’s Index and compare it to other version control systems while Joe is throwing shade, Michael learns a new command, and Allen makes it gross.

The full show notes for this episode are available at


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  • Ludum Dare is a bi-annual game jam that’s been running for over 20 years now. Jam #51 is coming up September 30th to October 3rd. (

The Index

Meet the Middle Man

  • The index refers to the set of blobs and trees created when running a git add, when you “stage” files.
  • These trees and blobs are not a part of the repository yet!
    • If you were to unstage the changes using a reset, you’d have an orphaned blob(s) that would eventually get cleaned up.
  • The index is a staging area for your next commit.
  • The staging area allows you to build up your next commit in stages.
  • You can almost ignore the index by doing a git commit -a (but shouldn’t).
  • In Subversion, the next set of changes is always determined by looking at the differences in the current working tree.
  • In Git, the next set of changes is determined by looking at your index and comparing that to the latest HEAD.
    • git add allows you to make additional changes before executing your commit with things like git add --patch and git add --interactive parameters.
    • For Emacs fans out there, the author mentioned gitsum. (GitHub)

Taking the Index Further

  • The author mentions “Quilt!”, is it this? (
    • The primary difference between Git and Quilt is Git only allows one patch to be constructed at a time.
  • Situation the author describes is: What if I had multiple changes I wanted to test independently with each other?
  • There isn’t anything built into Git to allow you to try out parallel sets of changes on the fly.
    • Multiple branches would allow you to try out different combinations and the index allows you to stage your changes in a series of commits, but you can’t do both at the same time.
    • To do this you’d need an index that allows for more than a single commit at a time.
    • Stacked Git is a tool that lets you prepare more than one index at a time. (
    • The author gives an example of using regular Git to do two commits by interactively selecting a patch.
    • Then, the author gives the example of how you’d have to go about disabling one set of changes to test the other set of changes. It’s not great … swapping between branches, cherry-picking changes, etc.
  • If you find yourself in this situation, definitely take a look at Stacked Git. Using Stacked Git, you are basically pushing and popping commits on a stack.

Resources we Like

Tip of the Week

  • Diffusion Bee is GUI for running Stable Diffusion on M1 macs. It’s got a one-click installer that you can get up and generating weird computer art in minutes … as long as you’re on a recent version of macOS and M1 hardware. (GitHub)
    • No M1 Mac? You can install the various packages you need to do it yourself, some assembly required! (
  • Git Tower is a fresh take on Git UI that lets you drag-n-drop branches, undo changes, and manage conflicts. Give it a shot! (
  • Git Kraken is the Gold Standard when it comes to Git UIs. It’s a rich, fully featured environment for managing all of your branches and changes. They are also the people behind the popular VS Code Extension GitLens (
  • GitHub CLI is an easy to use command line interface for interacting with GitHub. Reason 532 to love it … draft PR creation via gh pr create --draft ! (

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