How do I run an sbt main class from the shell as normal command-line program?

Question

How can I run an sbt app from the shell, so that I can run my app as a normal command-line program (as if run directly via scala but without having to set up an

Answer 1

Here's what I have in my SBT (version 0.10) project definition,

  val Mklauncher = config("mklauncher") extend(Compile)
  val mklauncher = TaskKey[Unit]("mklauncher")
  val mklauncherTask = mklauncher <<= (target, fullClasspath in Runtime) map { (target, cp) =>
    def writeFile(file: File, str: String) {
      val writer = new PrintWriter(file)
      writer.println(str)
      writer.close()
    }
    val cpString = cp.map(_.data).mkString(":")
    val launchString = """
CLASSPATH="%s"
scala -usejavacp -Djava.class.path="${CLASSPATH}" "$@"
""".format(cpString)
    val targetFile = (target / "scala-sbt").asFile
    writeFile(targetFile, launchString)
    targetFile.setExecutable(true)
  }

  ... // remember to add mklauncherTask to Project Settings

The mklauncher task creates a script target/scala-sbt that executes scala with the project classpath already set. It would be nice to have mklauncher executed automatically whenever the classpath changes, but I haven't looked into doing this yet.

(I use the Java classpath, rather than Scala's, for ease of creating embedded interpreters.)