diff --git a/util/complete/LineReader.scala b/util/complete/LineReader.scala
new file mode 100644
index 000000000..e7c9ec67a
--- /dev/null
+++ b/util/complete/LineReader.scala
@@ -0,0 +1,86 @@
+/* sbt -- Simple Build Tool
+ * Copyright 2008, 2009  Mark Harrah
+ */
+package sbt
+import jline.{Completor, ConsoleReader}
+abstract class JLine extends LineReader
+{
+	protected[this] val reader: ConsoleReader
+	def readLine(prompt: String) = JLine.withJLine { unsynchronizedReadLine(prompt) }
+	private[this] def unsynchronizedReadLine(prompt: String) =
+		reader.readLine(prompt) match
+		{
+			case null => None
+			case x => Some(x.trim)
+		}
+}
+private object JLine
+{
+	def terminal = jline.Terminal.getTerminal
+	def resetTerminal() = withTerminal { _ => jline.Terminal.resetTerminal }
+	private def withTerminal[T](f: jline.Terminal => T): T =
+		synchronized
+		{
+			val t = terminal
+			t.synchronized { f(t) }
+		}
+	def createReader() =
+		withTerminal { t =>
+			val cr = new ConsoleReader
+			t.enableEcho()
+			cr.setBellEnabled(false)
+			cr
+		}
+	def withJLine[T](action: => T): T =
+		withTerminal { t =>
+			t.disableEcho()
+			try { action }
+			finally { t.enableEcho() }
+		}
+	private[sbt] def initializeHistory(cr: ConsoleReader, historyPath: Option[Path]): Unit =
+		for(historyLocation <- historyPath)
+		{
+			val historyFile = historyLocation.asFile
+			ErrorHandling.wideConvert
+			{
+				historyFile.getParentFile.mkdirs()
+				val history = cr.getHistory
+				history.setMaxSize(MaxHistorySize)
+				history.setHistoryFile(historyFile)
+			}
+		}
+	def simple(historyPath: Option[Path]): SimpleReader = new SimpleReader(historyPath)
+	val MaxHistorySize = 500
+}
+
+trait LineReader extends NotNull
+{
+	def readLine(prompt: String): Option[String]
+}
+private[sbt] final class LazyJLineReader(historyPath: Option[Path], completor: => Completor) extends JLine
+{
+	protected[this] val reader =
+	{
+		val cr = new ConsoleReader
+		cr.setBellEnabled(false)
+		JLine.initializeHistory(cr, historyPath)
+		cr.addCompletor(new LazyCompletor(completor))
+		cr
+	}
+}
+private class LazyCompletor(delegate0: => Completor) extends Completor
+{
+	private lazy val delegate = delegate0
+	def complete(buffer: String, cursor: Int, candidates: java.util.List[_]): Int =
+		delegate.complete(buffer, cursor, candidates)
+}
+
+class SimpleReader private[sbt] (historyPath: Option[Path]) extends JLine
+{
+	protected[this] val reader = JLine.createReader()
+	JLine.initializeHistory(reader, historyPath)
+}
+object SimpleReader extends JLine
+{
+	protected[this] val reader = JLine.createReader()
+}
\ No newline at end of file