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Getting Started Running

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Havoc Pennington edited this page Oct 19, 2011 · 15 revisions

Running

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This page describes how to use sbt once you have set up your project. It assumes you've installed sbt and created a Hello, World or other project.

Interactive mode

Run sbt in your project directory with no arguments:

$ sbt

Running sbt with no command line arguments starts it in interactive mode. Interactive mode has a command prompt (with tab completion and history!).

For example, you could type compile at the sbt prompt:

> compile

To compile again, press up arrow and then enter.

To run your program, type run.

To leave interactive mode, type exit or use Ctrl+D (Unix) or Ctrl+Z (Windows).

Batch mode

You can also run sbt in batch mode, specifying a space-separated list of sbt actions as arguments. For sbt commands that take arguments, pass the command and arguments as one argument to sbt by enclosing them in quotes. For example,

$ sbt clean compile "test-only TestA TestB"

In this example, test-only has arguments, TestA and TestB. The actions will be run in sequence (clean, compile, then test-only).

Continuous build and test

To speed up your edit-compile-test cycle, you can ask sbt to automatically recompile or run tests whenever you save a source file.

Make an action run when one or more source files change by prefixing the action with ~. For example, in interactive mode try:

> ~ compile

Press enter to stop watching for changes.

You can use the ~ prefix with either interactive mode or batch mode.

See Triggered Execution for more details.

Common actions

Here are some of the most common sbt commands. For a more complete list, see Command Line Reference.

  • clean Deletes all generated files (the target directory).
  • compile Compiles the main sources (in the src/main/scala directory).
  • test Compiles and runs all tests.
  • console Starts the Scala interpreter with a classpath including the compiled sources and all dependencies. To return to sbt, type :quit, Ctrl+D (Unix), or Ctrl+Z (Windows).
  • run <argument>* Runs the main class for the project in the same virtual machine as sbt.
  • package Creates a jar file containing the files in src/main/resources and the classes compiled from src/main/scala.
  • help <command> Displays detailed help for the specified command. If no command is provided, displays brief descriptions of all commands.
  • reload Reloads the build definition (build.sbt, project/*.scala, project/*.sbt files). Needed if you change the build definition.

Tab completion

Interactive mode has tab completion, including at an empty prompt. A special sbt convention is that pressing tab once may show only a subset of most likely completions, while pressing it more times shows more verbose choices.

History Commands

Interactive mode remembers history, even if you exit sbt and restart it. The simplest way to access history is with the up arrow key. The following commands are also supported:

  • ! Show history command help.
  • !! Execute the previous command again.
  • !: Show all previous commands.
  • !:n Show the last n commands.
  • !n Execute the command with index n, as shown by the !: command.
  • !-n Execute the nth command before this one.
  • !string Execute the most recent command starting with 'string'
  • !?string Execute the most recent command containing 'string'

Next

Move on to understanding build.sbt.

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