dandavison/delta

> A syntax-highlighting pager that reformats git, diff, grep, and blame output — it styles diffs, it does not compute them.

GitHub repo · Official website · License: MIT

Overview

Delta is a terminal pager written in Rust that sits between git and your terminal, reparsing unified-diff output and re-emitting it with syntax highlighting, word-level change highlighting, line numbers, and optional side-by-side layout¹. The package is named git-delta in most package managers, but the executable is delta. It is not a diff algorithm: git (or diff, grep, rg) still produces the diff; delta only restyles the stream.

The core value is legibility. Standard git diff marks changes at line granularity with red/green; delta adds language-aware syntax highlighting (via the same theme and grammar assets used by sharkdp/bat), infers within-line edits with a Levenshtein-based algorithm to highlight just the changed tokens, and can render two-column side-by-side views with wrapping. It also improves git blame, merge-conflict display, and grep output from rg / git grep.

The defining tension is configuration surface versus a clean default. Delta is heavily customizable — 20-plus stylable elements, box/line decorations, named feature presets, emulation modes for diff-highlight and diff-so-fancy — and that flexibility is the draw, but the same surface makes it easy to end up with a .gitconfig [delta] block nobody remembers the meaning of. It is a polished, actively maintained tool (31k stars, last pushed within days as of 2026), carrying a large open-issue backlog (~400) typical of a popular, option-rich CLI².

Getting Started

Install (Homebrew shown; also in apt, dnf, pacman, cargo, scoop, etc.³):

brew install git-delta

Add to ~/.gitconfig:

[core]
    pager = delta
[interactive]
    diffFilter = delta --color-only
[delta]
    navigate = true      # n / N jump between diff sections
    side-by-side = true
    line-numbers = true
[merge]
    conflictStyle = zdiff3

Then git diff, git show, git log -p, and git blame route through delta automatically. delta --help prints the full manual; delta --show-syntax-themes previews color themes.

Architecture / How It Works

Delta is a streaming line processor, not a differ. Its input is the ANSI or plain text that git/diff/grep already emit; it detects structural markers (diff --git, @@ hunk headers, +/- lines, commit and file headers) and rewrites each region. Because it consumes git's own output, in interactive contexts like git add -p it must be invoked as delta --color-only through interactive.diffFilter so it restyles rather than re-parses already-processed content.

Syntax highlighting is provided by the syntect crate operating over Sublime Text grammar and theme assets — the same asset set as bat, which is why every bat theme is available in delta¹. Highlighting is applied per line within a hunk after delta has classified the line as added/removed/context. Word-level ("intra-line") highlighting runs an edit-distance inference between the removed and added versions of a changed line to mark the minimal changed span rather than the whole line.

Layout is computed after styling: line numbers, side-by-side column splitting, and line wrapping are presentation passes over the classified, highlighted lines. Delta does not page on its own — by default it shells out to less (honoring PAGER/DELTA_PAGER), passing flags for raw ANSI and, when navigate is set, search patterns that implement the n/N section jumping. --hyperlinks emits OSC 8 terminal escape sequences so commit hashes and file paths become clickable, with hosting-provider URL templates for GitHub, GitLab, SourceHut, and Codeberg.

Production Notes

• It renders diffs, it doesn't diff. Delta cannot show semantic/structural

changes; a reformatted line still appears as a full delete+add. For AST-aware diffing use difftastic instead — a different category of tool.

• Paging quirks come from less. Most "delta doesn't scroll / colors look

wrong / output truncated" reports trace to the underlying pager and the LESS environment. Truecolor requires a 24-bit-capable terminal; on 256-color terminals themes degrade to the nearest palette. If output is being captured or piped, set --paging=never.

• --color-only in interactive mode is mandatory. Omitting it from

interactive.diffFilter produces broken or doubly-escaped output in git add -p and similar flows, because delta would be reparsing colored input.

• Large diffs cost CPU. Syntax highlighting and intra-line inference are

per-line work; very large diffs (generated files, vendored trees, lockfiles) are noticeably slower than raw git. Restrict with pathspecs or drop delta for those cases.

• Copy-paste is a feature, not free. By default delta strips leading

+/- markers so code copies cleanly out of the diff — convenient, but it means what you see is not byte-identical to raw diff text.

• Merge-conflict display wants zdiff3. Delta's improved conflict rendering

assumes git's zdiff3 conflict style; with the older merge style the output is less useful.

• Config drift. Feature presets and the [delta] block accumulate. Prefer

named [delta "feature"] groupings activated via features = so intent stays legible, and re-check with delta --help after upgrades since option names and defaults have shifted across releases.

When to Use / When Not

Use when:

• You read diffs, blame, or log -p in a terminal daily and want syntax

highlighting and clearer change markers.

• You want side-by-side review without leaving the CLI.
• You already use bat and want matching themes across your tooling.
• You want a drop-in that stays close to git's default semantics.

Avoid when:

• You need structural/semantic diffs (renamed variables, moved blocks) — use an

AST differ.

• You run in constrained or non-truecolor terminals where the styling degrades

and adds little.

• You want zero-config: delta's payoff comes with some .gitconfig investment.
• You are scripting/parsing diff output downstream — pipe raw git, not delta.

Alternatives

• so-fancy/diff-so-fancy — use when you want a lighter, Perl-based prettifier

and don't need syntax highlighting or side-by-side; delta can emulate it.

• Wilfred/difftastic — use when you want structural, syntax-aware diffs that

actually understand the language, not just highlighting.

• sharkdp/bat — use for paging/printing files generally; it's the sibling that

shares delta's highlighting assets but is not diff-specialized.

• walles/riff — use when you want a smaller Rust diff refiner focused on

intra-line highlighting with less configuration.

• git contrib diff-highlight — use when you want the minimal, dependency-free

option shipped with git itself.

History

Exact per-version release dates are not restated here to avoid false precision; see the repository's tags and CHANGELOG for the authoritative timeline⁴.

References

1. ^ dandavison/delta README — features and bat theme/grammar sharing. https://github.com/dandavison/delta
2. ^ GitHub API, repos/dandavison/delta — 31,436 stars, 550 forks, ~407 open issues, MIT, created 2019-06-24, last push 2026-07-05 (fetched 2026-07-15).
3. ^ Delta installation guide. https://dandavison.github.io/delta/installation.html
4. ^ Delta releases and tags. https://github.com/dandavison/delta/releases

Tags

rust, cli, git, diff, pager, syntax-highlighting, terminal, developer-tools, code-review, blame