alt.hn

2/26/2026 at 5:54:06 PM

Show HN: Deff – Side-by-side Git diff review in your terminal

 https://github.com/flamestro/deff

by flamestro

2/26/2026 at 7:27:23 PM

I was looking for a good TUI tool for diffs recently, but I'm not sure yet if what I want exists already (and I don't think this tool does it (yet?)). I've been moving my workflow out of VSCode as I'm using TUI-driven coding agents more often lately but one thing I miss from my VSCode/GitHub workflow is the ability to provide a comment on lines or ranges in a diff to provide targeted feedback to the agent. Most diff tools seem to be (rightfully) focused on cleanly visualizing changes and not necessarily iterating on the change.

I admit I haven't looked super hard yet, I settled on configuring git to use delta [0] for now and I'm happy with it, but I'm curious if anyone has a workflow for reviewing/iterating on diffs in the terminal that they'd be willing to share. Also open to being told that I'm lightyears behind and that there's a better mental model for this.

[0] https://github.com/dandavison/delta/

by llbbdd

2/26/2026 at 10:00:05 PM

I had tried `delta` a few years ago but eventually went with `diff-so-fancy`[1]

The two are kind of similar if I remember correctly, and both offer a lot of config options to change the style and more. I mostly use it for diffs involving long lines since it highlights changes within a line, which makes it easier to spot such edits.

I have an alias set in `~/.gitconfig` to pipe the output of `git diff` (with options) to `diff-so-fancy` with `git diffs`:

    diffs = "!f() { git diff $@ | diff-so-fancy; }; f"
[1] https://github.com/so-fancy/diff-so-fancy

by thamer

2/26/2026 at 8:01:26 PM

Octo [0] for nvim lets you submit reviews, add comments on ranges, reply to threads, etc.

This in conjunction with gh-dash [1] to launch a review can get you a pretty nice TUI review workflow.

[0] https://github.com/pwntester/octo.nvim

[1] https://github.com/dlvhdr/gh-dash

*Edit: I see you meant providing feedback to an agent, not a PR. Well that's what I get for reading too fast.

by kodomomo

2/26/2026 at 9:38:37 PM

No problem, I appreciate another reason to look at Neovim; I do sometimes have a need to interact with GH's actual PR flow and once I've moved the rest of my workflow out of VSCode, Neovim looks like the best option for the last mile of actually writing and editing code. I just have to commit the time to set it up with everything I probably take for granted in VSCode's editor.

by llbbdd

2/26/2026 at 9:28:12 PM

I was also searching for some time, but most of them did not have enough context for my workflow tbh. So thats why I decided to make deff. Another good one I liked is vimdiff

by flamestro

2/26/2026 at 8:40:48 PM

I use delta for quick diffs in a shell (along with the -U0 option on git-diff), but in my claude workflow, i have a 3 pane setup in tmux: :| where the right side is a claude session, the top left is emacs opened to magit, and the bottom left is a shell. Magit makes navigating around a diff pretty easy (as well as all the other git operations), and I can dive into anything and hand edit as well.

by mckn1ght

2/26/2026 at 8:43:05 PM

Not TUI based but I made something called meatcheck. The idea being that the LLM requests a review from the human, you can leave inline comments like a PR review.

Once you submit it outputs to stdout and the agent reads your comments and actions them.

https://github.com/jfyne/meatcheck

by jfyne

2/26/2026 at 10:01:57 PM

Thank you! At a glance this is very close to what I had in mind, especially with the straightforward output format, I'll give this a try.

by llbbdd

2/26/2026 at 8:46:49 PM

magit

by coryrc

2/26/2026 at 7:44:52 PM

What I would love to see is "tig" replacement that is:

- even faster, especially if you have couple thousand files and just want to press "u" for some time and see them very quickly all get staged

- has this split-view diff opened for a file

Otherwise tig is one of my favorite tools to quickly commit stuff without too many key presses but with review abilities, i have its "tig status" aliased to "t"

by k_bx

2/26/2026 at 6:53:35 PM

I have been using https://github.com/jeffkaufman/icdiff for the longest time to get side by side diffs.

by meain

2/26/2026 at 9:09:32 PM

This looks great as well! I personally prefer a bit more context. Thats why I added a bit more of it to deff. It also allows to mark files as reviewed by pressing `r` which is quite handy for my flow.

by flamestro

2/26/2026 at 7:01:34 PM

I also use icdiff, but it is good to have the file-awareness for git diff esp. the ability to quickly skip files that I know aren't important.

by lf-non

2/26/2026 at 7:32:33 PM

For that in particular, I use delta (<https://github.com/dandavison/delta>) with `side-by-side = true` enabled. I find I use both icdiff and delta side-by-side on a regular basis.

by Amorymeltzer

2/26/2026 at 7:41:18 PM

Delta is so much faster than icdiff too.

by behnamoh

2/26/2026 at 7:03:18 PM

getting users to adopt a new tool with its own incantations is a tough sell. git supports specifying an external pager so folks can plug in alternatives (such as https://github.com/dandavison/delta) while still using the familiar git frontend

by rileymichael

2/26/2026 at 7:53:02 PM

[flagged]

by greaakdls

2/26/2026 at 7:30:08 PM

Why shouldn't this be a simple wrapper to tie Delta to some kind of file browser or a thing like television[1]?

[1]: https://alexpasmantier.github.io/television/

by ZoomZoomZoom

2/26/2026 at 8:07:09 PM

television??

by syngrog66

2/26/2026 at 7:13:22 PM 

    git difftool --tool=vimdiff

by yottamus

2/26/2026 at 9:12:28 PM

I personally find vimdiff a bit harder to navigate for my usecase. The reason is that I am context unaware of the file often in larger projects and wanted something that allows me to check all lines in a touched file. However, I have to admit vimdiff comes quite close to what I need and is a great tool!

by flamestro

2/26/2026 at 7:21:13 PM

but is it blazingly fast?

by metalliqaz

2/26/2026 at 8:06:11 PM

if its not in Rust or browser-based or a "cloud" service or the result of multi-GWH of LLM "training" or a VSCode plugin or ideally all of the prior then the HN kids wont be interested :-)

by syngrog66

2/26/2026 at 7:28:57 PM

The specific gap side-by-side covers for me is reviewing changes on a remote box without firing up an IDE. Delta is great but keeps the unified format. icdiff does the split view but is pretty barebones. So there's definitely space here.

What nobody's mentioned yet is difftastic. Takes a completely different approach - parses syntax trees instead of lines, so indentation changes and bracket shuffles don't show up as noise. Worth a look if you're comparing options.

Main question I'd have: how does it hold up on large files? 5k+ line diffs are where most of these tools either choke or produce unreadable output. That'd be the test I'd run first.

by jamiecode

2/26/2026 at 9:14:43 PM

So I tested this on huge files (checking cargo lock for instance) and it is super fast in the navigation of those. Until now I did not encounter any issue with bigger files (around 4k-6k changes but also only 4k-6k lines).

by flamestro

2/26/2026 at 8:03:49 PM

Looks interesting. I'm currently using https://tuicr.dev/ , of which I like that the first screen it shows is the choice of commit range you want to review. Might be something to consider for deff?

by raphinou

2/26/2026 at 9:51:42 PM

It blows my mind that nowadays, some random tools on internet tells you to do "curl -fsSL https://.... | bash" to install some "binary" things and a lot of people will do it without hesitation.

It probably explains why there is so many data leaks recently but it is like we did a 20 years jump back in time in terms of security in just a few years.

by greatgib

2/26/2026 at 10:21:39 PM

One day folks who live inside commandlines and TUIs all day will realize that there's nothing particular about webapps or the sandboxes that they execute in that requires we build exclusively graphical runtimes around them, instead of taking advantage of the same security and distribution model for programs accessible and usable from within terminal emulator.

by pwdisswordfishy

2/26/2026 at 9:58:59 PM

I get the hesitation :D But the code is open and the install.sh is as minimal as it gets tbh. Still, as said, I get the hesitation. What a time to be alive.

It does not install binaries, it builds the binary by checking out the project basically. You can also do the process manually and use the tool.

by flamestro

2/26/2026 at 10:04:15 PM

> But the code is open and the install.sh is as minimal as it gets tbh.

I bet 99.9999% of users do not review the code nor the install script.

by warkdarrior

2/26/2026 at 10:26:29 PM

Is it that different from downloading and running a binary?

by jaden

2/26/2026 at 10:05:41 PM

Cowboys rule the internet.

by holoduke

2/26/2026 at 10:14:47 PM

will this play well with jj?

by zem

2/26/2026 at 7:39:03 PM 

  emacs --eval='(ediff-files "file1" "file2")'
(The “|” key toggles side-by-side view.)

by teddyh

2/26/2026 at 9:15:17 PM

Yes, but emacs < vim

by flamestro

2/26/2026 at 7:46:21 PM

[dead]

by dingnuts

2/26/2026 at 8:14:35 PM

vimdiff is pretty fast, and is likely installed on your linux system without you realizing it.

by hatradiowigwam

2/26/2026 at 9:15:45 PM

Its a great tool, but misses some of the context I needed.

by flamestro

2/26/2026 at 9:12:40 PM

looks pretty good at a glance, though I would like to see three views for handling conflicts. Target on the left, source on the right, and the combined result in the middle.

...I really just like the way the Jetbrains IDEs do it, and I wish there were a TUI version that I could launch automatically from the git cli.

by dec0dedab0de

2/26/2026 at 8:29:47 PM

we need something like this in lazygit -- which is excellent all around but lacking in visual diffing/merging.

What is most useful though is a 3-panel setup, like JetBrains -- still the best git client I have worked with.

by insane_dreamer

2/26/2026 at 9:16:53 PM

What would the third panel contain in this case? Do you mean the setup that IntelliJ has in merge conflicts?

by flamestro