Justfile Authoring

Follow existing conventions

• •Locate the nearest justfile or .justfile to the working directory and edit in place.
• •Preserve naming style, indentation, and grouping conventions.
• •Keep diffs minimal; avoid renaming recipes unless requested.

Edit workflow

1. •Read the existing justfile top to bottom; note set directives, variables, aliases, and groups.
2. •Add or update recipes using the same structure and indentation.
3. •Ensure dependencies and parameters are correct and consistent.
4. •If a recipe should be hidden from listings, mark it private or prefix with _.

Syntax essentials

• •

  Recipe:

  just

  build target="app": clean
      cargo build --release --bin {{target}}
  

• •

  Dependencies: run before the recipe body; parameterized deps are wrapped in parentheses.

  just

  rebuild: clean build
  build arch: (clean arch)
      cargo build --target {{arch}}
  

• •

  Parameters: defaults supported; variadics use * (zero or more) or + (one or more).

  just

  test suite="all":
      cargo test --tests {{suite}}
  
  backup *files:
      tar czf backup.tar.gz {{files}}
  

• •

  Exported parameters: prefix with $ to pass as environment variables.

  just

  test-with-env $TEST_MODE:
      echo "$TEST_MODE"
  

• •

  Variables and interpolation:

  just

  app := "myapp"
  build:
      echo "{{app}}"
  

• •

  Default recipe: place first if you want it to run with just.

  just

  default:
      @just --list
  

Settings

Use set to configure behavior globally.

set dotenv-load := true
set shell := ["bash", "-eo", "pipefail", "-c"]
set working-directory := "ios"

Attributes and helpers

Common attributes:

• •[group('name')] or [group: 'name'] to categorize recipes in listings.
• •[working-directory('path')] to override the cwd for one recipe.
• •[private] to hide a recipe or alias from just --list.
• •[doc('description')] to control list output text.
• •[confirm('prompt')] to request confirmation.
• •[linux], [macos], [windows] for platform-specific recipes.
• •[no-cd] to run in the invoking directory instead of the justfile directory.
• •[positional-arguments] for positional-argument recipes.

Aliases:

alias b := build

Shebang recipes

For multi-line scripts, start the body with a shebang.

release:
    #!/usr/bin/env bash
    set -euo pipefail
    ./scripts/release.sh

Editing checklist

• •Keep indentation consistent (spaces or tabs, not both, within a recipe).
• •Use @ on a line (or @ before the recipe name) to suppress command echoing.
• •Prefer group and doc attributes for clarity in just --list.
• •Avoid unused variables, aliases, or recipes.
• •For repo-specific paths, anchor to the existing working-directory conventions.