scala-cli

Modern Scala command-line runner and build tool

TLDR

Run Scala script

$ scala-cli [script.sc]

Run Scala file

$ scala-cli run [Main.scala]

Start REPL

$ scala-cli repl

Compile to JAR

$ scala-cli package [src/] -o [app.jar]

Run tests

$ scala-cli test [src/]

Add a dependency and run

$ scala-cli run --dep [com.lihaoyi::os-lib:0.9.1] [script.scala]

Watch for changes and re-run

$ scala-cli run --watch [Main.scala]

SYNOPSIS

scala-cli [command] [options] [inputs...]

scala-cli is the modern Scala command line tool, adopted as the official `scala` command since Scala 3.5. It runs scripts, compiles projects, manages dependencies, and creates executables. Designed for both learning and production Scala development.
Scala-CLI supports using directives (comments like `//> using dep`) within source files to declare dependencies, Scala versions, and compiler options without a separate build file. This makes it ideal for scripts and small projects.

PARAMETERS

run

Run Scala code.

repl

Start interactive REPL.

compile

Compile sources.

package

Create JAR or native image.

test

Run tests.

fmt

Format code.

-S version, --scala version

Set Scala version (e.g., 3.3, 2.13).

--dep dependency

Add dependency (e.g., com.lihaoyi::os-lib:0.9.1).

-O option

Scala compiler option.

-w, --watch

Watch sources and re-run on changes.

setup-ide

Generate IDE configuration files (BSP).

publish

Publish library to Maven repository.

--native

Compile to Scala Native binary.

--js

Compile to Scala.js JavaScript.

CAVEATS

For large multi-module projects, a dedicated build tool like sbt or Mill is more appropriate. Using directives in source files are a Scala-CLI feature and not standard Scala.