Just in Time

Just is a command runner that lets you define project-specific tasks in a declarative justfile.

- BY MARCIN GASTOL

Modern Linux development often involves juggling various scripts and makefiles to automate tasks such as building software, running tests, or managing environments. Just is a relatively new task runner — essentially a command runner — offering a fresh alternative to ad-hoc Bash scripts and GNU Make for project automation. Unlike traditional build systems, Just focuses on simplicity and consistency, providing a streamlined way to define and run project-specific commands via a justfile.

Why Just?

Seasoned Linux users often default to Bash scripts or makefiles for project automation. Bash scripts are straightforward but can become messy as a project grows, lacking a unified interface for running various tasks. GNU Make, on the other hand, provides a formal structure but comes with historical quirks (such as tab-indentation issues and implicit rules) and is meant primarily for build automation with file targets. Just positions itself as a “command runner, not a build system,” avoiding much of Make's complexity. In practical terms, this means no need for managing phony targets — every Just recipe is essentially “phony” by default, because Just doesn't track file timestamps or rebuild logic. Just brings several advantages for Linux automation:

Simple, File-Based Task Definitions. You put your commands in a file literally named justfile (no extension, typically at the project root), with a syntax reminiscent of Make but more forgiving (spaces instead of hard tabs; no cryptic $@ variables unless you add them yourself).