just

casey/justReviewed by AI

What it does

just is a small terminal program that keeps a project's commands in a file called `justfile`. Each entry, called a recipe, has a name and the lines to run, so instead of remembering a long command you type `just test` or `just build`. Recipes take arguments, can depend on each other, can run in parallel and can even be written in Python or another language. It is one 2 MB file for Windows, macOS and Linux, is in nearly every package manager, and the author describes it as simpler than `make`.

How easy it is to install

C · install 1 or 2 tools · Windows

Windows C
macOS C
Linux C

One ready 2 MB file on all three systems, by package manager (`winget install --id Casey.Just --exact`, `brew install just`, `apt install just`) or straight from the releases page. It stays at C because there is no window: you write a `justfile` by hand and run everything from the terminal. On Windows there is an extra catch: the README says recipes need an `sh` from Git for Windows, GitHub Desktop or Cygwin, unless you add `set shell := ["powershell.exe", "-c"]`.

Numbers on GitHub

Stars: 36,494on Oct 31, 2026
Downloads: 66,530,6051,643,302 this week
Growth: +51stars in 5 days

Stars over time

Facts

Runs on: Windows, macOS, Linux
You need to install: Nothing extra
To build from source: Rust
Disk space: 2 MB–7 MB · from the installer
Accounts or keys: None
Cost: Free · Free. The licence is CC0-1.0, a public-domain dedication, so the author gives up copyright claims; the text notes trademark and patent rights are not waived.
License: CC0-1.0 (Permissive)
Last update: Oct 27, 2026

Risk signals (4)

Attentionruns whatever commands the justfile contains
Typing `just` with no arguments "runs the recipe with the [default] attribute, or the first recipe in the justfile", and the README states "Recipes can be written in arbitrary languages, like Python or Node.js". A justfile that came with a project you downloaded can therefore run anything on your computer, so it is worth reading before you run it.
AI review
AttentionInstall command runs a script from the internet
The README offers this install route: `curl --proto '=https' --tlsv1.2 -sSf https://just.systems/install.sh | bash -s -- --to DEST`, which runs a script fetched from the internet without you reading it first. The package managers and the release archives avoid that.
AI review
Inforeleases include checksums
README: "Releases include a SHA256SUM file which can be used to verify the integrity of pre-built binary archives", checked with `shasum --algorithm 256 --ignore-missing --check SHA256SUMS`. Verifying is a manual step.
AI review
Infopromises not to break existing files
README, Backwards Compatibility: "Future releases will not introduce backwards incompatible changes that make existing justfiles stop working" and "There will never be a just 2.0". Features still in flux are behind `--unstable` or `set unstable`. The project has 147 releases since 2016 and the last one is 1.59.0 from 2026-10-15.
AI review

Evidence is shown in its original language.

What Radar could not check

Whether your Windows setup has an `sh` on the PATH, which the README requires unless you change the shell setting
Which version your package manager installs, which can lag behind 1.59.0
What a `justfile` written by somebody else actually does when you run it
Whether recipes written for Unix shells behave the same under PowerShell, which the README warns about for positional arguments