Put repeatable project commands in a Justfile

Create a Justfile with a parameterized greeting and a test recipe, then run it from a project subdirectory.

how-to3 steps

Updated

in short

Store repeatable commands as named recipes in a justfile. Pass recipe arguments on the command line and use --list to discover available commands.

Use the small fixture below to check the workflow before applying it to your own project.

Tools used

Before you start

  • A Bash or Zsh terminal on Linux or macOS
  • The listed tools installed and available on PATH

Steps

  1. Step 1: Create the recipes

    The @ prefix hides the command itself while retaining its output.

    sh
    trmn_guide_dir="$(mktemp -d)"
cd "$trmn_guide_dir"
cat > justfile <<'EOF'
greet name="developer":
    @printf 'Hello, %s!\n' '{{name}}'

test:
    @printf 'tests passed\n'
EOF

  2. Step 2: Discover and run recipes

    Use a simple name for this example; template substitution is not a general shell-escaping mechanism.

    sh
    just --list
just greet Ada
just test

  3. Step 3: Run from a subdirectory

    just searches upward for a justfile and runs these recipes from its directory.

    sh
    mkdir src
cd src
just greet Ada
    output
    Hello, Ada!

Further reading

[Just manual](https://just.systems/man/en/)

FAQ

Does just rebuild only changed files?
No. This example uses just as a command runner. Use a build system when you need file dependency tracking.
Can I safely substitute arbitrary user input?
Do not interpolate untrusted text into recipe shell commands. Quoting and argument handling need separate consideration.

related

just details