diff --git a/src/Pure/System/bash.scala b/src/Pure/System/bash.scala
--- a/src/Pure/System/bash.scala
+++ b/src/Pure/System/bash.scala
@@ -1,203 +1,188 @@
 /*  Title:      Pure/System/bash.scala
     Author:     Makarius
 
 GNU bash processes, with propagation of interrupts.
 */
 
 package isabelle
 
 
 import java.io.{File => JFile, BufferedReader, InputStreamReader,
   BufferedWriter, OutputStreamWriter}
 
 import scala.annotation.tailrec
 
 
 object Bash
 {
   /* concrete syntax */
 
   private def bash_chr(c: Byte): String =
   {
     val ch = c.toChar
     ch match {
       case '\t' => "$'\\t'"
       case '\n' => "$'\\n'"
       case '\f' => "$'\\f'"
       case '\r' => "$'\\r'"
       case _ =>
         if (Symbol.is_ascii_letter(ch) || Symbol.is_ascii_digit(ch) || "+,-./:_".contains(ch))
           Symbol.ascii(ch)
         else if (c < 0) "$'\\x" + Integer.toHexString(256 + c) + "'"
         else if (c < 16) "$'\\x0" + Integer.toHexString(c) + "'"
         else if (c < 32 || c >= 127) "$'\\x" + Integer.toHexString(c) + "'"
         else  "\\" + ch
     }
   }
 
   def string(s: String): String =
     if (s == "") "\"\""
     else UTF8.bytes(s).iterator.map(bash_chr).mkString
 
   def strings(ss: List[String]): String =
     ss.iterator.map(Bash.string).mkString(" ")
 
 
   /* process and result */
 
-  private class Limited_Progress(proc: Process, progress_limit: Option[Long])
-  {
-    private var count = 0L
-    def apply(progress: String => Unit)(line: String): Unit = synchronized {
-      progress(line)
-      count = count + line.length + 1
-      progress_limit match {
-        case Some(limit) if count > limit => proc.terminate
-        case _ =>
-      }
-    }
-  }
-
   def process(script: String,
       cwd: JFile = null,
       env: Map[String, String] = Isabelle_System.settings(),
       redirect: Boolean = false,
       cleanup: () => Unit = () => ()): Process =
     new Process(script, cwd, env, redirect, cleanup)
 
   class Process private[Bash](
       script: String,
       cwd: JFile,
       env: Map[String, String],
       redirect: Boolean,
       cleanup: () => Unit)
   {
     private val timing_file = Isabelle_System.tmp_file("bash_timing")
     private val timing = Synchronized[Option[Timing]](None)
     def get_timing: Timing = timing.value getOrElse Timing.zero
 
     private val script_file = Isabelle_System.tmp_file("bash_script")
     File.write(script_file, script)
 
     private val proc =
       Isabelle_System.process(
         List(File.platform_path(Path.variable("ISABELLE_BASH_PROCESS")), "-",
           File.standard_path(timing_file), "bash", File.standard_path(script_file)),
         cwd = cwd, env = env, redirect = redirect)
 
 
     // channels
 
     val stdin: BufferedWriter =
       new BufferedWriter(new OutputStreamWriter(proc.getOutputStream, UTF8.charset))
 
     val stdout: BufferedReader =
       new BufferedReader(new InputStreamReader(proc.getInputStream, UTF8.charset))
 
     val stderr: BufferedReader =
       new BufferedReader(new InputStreamReader(proc.getErrorStream, UTF8.charset))
 
 
     // signals
 
     private val pid = stdout.readLine
 
     @tailrec private def kill(signal: String, count: Int = 1): Boolean =
     {
       count <= 0 ||
       {
         Isabelle_System.kill(signal, pid)
         val running = Isabelle_System.kill("0", pid)._2 == 0
         if (running) {
           Time.seconds(0.1).sleep
           kill(signal, count - 1)
         }
         else false
       }
     }
 
     def terminate(): Unit = Isabelle_Thread.try_uninterruptible
     {
       kill("INT", count = 7) && kill("TERM", count = 3) && kill("KILL")
       proc.destroy
       do_cleanup()
     }
 
     def interrupt(): Unit = Isabelle_Thread.try_uninterruptible
     {
       Isabelle_System.kill("INT", pid)
     }
 
 
     // JVM shutdown hook
 
     private val shutdown_hook = Isabelle_Thread.create(() => terminate())
 
     try { Runtime.getRuntime.addShutdownHook(shutdown_hook) }
     catch { case _: IllegalStateException => }
 
 
     // cleanup
 
     private def do_cleanup()
     {
       try { Runtime.getRuntime.removeShutdownHook(shutdown_hook) }
       catch { case _: IllegalStateException => }
 
       script_file.delete
 
       timing.change {
         case None =>
           if (timing_file.isFile) {
             val t =
               Word.explode(File.read(timing_file)) match {
                 case List(Value.Long(elapsed), Value.Long(cpu)) =>
                   Timing(Time.ms(elapsed), Time.ms(cpu), Time.zero)
                 case _ => Timing.zero
               }
             timing_file.delete
             Some(t)
           }
           else Some(Timing.zero)
         case some => some
       }
 
       cleanup()
     }
 
 
     // join
 
     def join: Int =
     {
       val rc = proc.waitFor
       do_cleanup()
       rc
     }
 
 
     // result
 
     def result(
       progress_stdout: String => Unit = (_: String) => (),
       progress_stderr: String => Unit = (_: String) => (),
-      progress_limit: Option[Long] = None,
       strict: Boolean = true): Process_Result =
     {
       stdin.close
 
-      val limited = new Limited_Progress(this, progress_limit)
       val out_lines =
-        Future.thread("bash_stdout") { File.read_lines(stdout, limited(progress_stdout)) }
+        Future.thread("bash_stdout") { File.read_lines(stdout, progress_stdout) }
       val err_lines =
-        Future.thread("bash_stderr") { File.read_lines(stderr, limited(progress_stderr)) }
+        Future.thread("bash_stderr") { File.read_lines(stderr, progress_stderr) }
 
       val rc =
         try { join }
         catch { case Exn.Interrupt() => terminate(); Exn.Interrupt.return_code }
       if (strict && rc == Exn.Interrupt.return_code) throw Exn.Interrupt()
 
       Process_Result(rc, out_lines.join, err_lines.join, false, get_timing)
     }
   }
 }
diff --git a/src/Pure/System/isabelle_system.scala b/src/Pure/System/isabelle_system.scala
--- a/src/Pure/System/isabelle_system.scala
+++ b/src/Pure/System/isabelle_system.scala
@@ -1,407 +1,406 @@
 /*  Title:      Pure/System/isabelle_system.scala
     Author:     Makarius
 
 Fundamental Isabelle system environment: quasi-static module with
 optional init operation.
 */
 
 package isabelle
 
 
 import java.io.{File => JFile, IOException}
 import java.nio.file.{Path => JPath, Files, SimpleFileVisitor, FileVisitResult}
 import java.nio.file.attribute.BasicFileAttributes
 
 import scala.collection.mutable
 
 
 object Isabelle_System
 {
   /** bootstrap information **/
 
   def jdk_home(): String =
   {
     val java_home = System.getProperty("java.home", "")
     val home = new JFile(java_home)
     val parent = home.getParent
     if (home.getName == "jre" && parent != null &&
         (new JFile(new JFile(parent, "bin"), "javac")).exists) parent
     else java_home
   }
 
   def bootstrap_directory(
     preference: String, envar: String, property: String, description: String): String =
   {
     val value =
       proper_string(preference) orElse  // explicit argument
       proper_string(System.getenv(envar)) orElse  // e.g. inherited from running isabelle tool
       proper_string(System.getProperty(property)) getOrElse  // e.g. via JVM application boot process
       error("Unknown " + description + " directory")
 
     if ((new JFile(value)).isDirectory) value
     else error("Bad " + description + " directory " + quote(value))
   }
 
 
 
   /** implicit settings environment **/
 
   abstract class Service
 
   @volatile private var _settings: Option[Map[String, String]] = None
   @volatile private var _services: Option[List[Service]] = None
 
   def settings(): Map[String, String] =
   {
     if (_settings.isEmpty) init()  // unsynchronized check
     _settings.get
   }
 
   def services(): List[Service] =
   {
     if (_services.isEmpty) init()  // unsynchronized check
     _services.get
   }
 
   def init(isabelle_root: String = "", cygwin_root: String = ""): Unit = synchronized
   {
     if (_settings.isEmpty || _services.isEmpty) {
       val isabelle_root1 =
         bootstrap_directory(isabelle_root, "ISABELLE_ROOT", "isabelle.root", "Isabelle root")
 
       val cygwin_root1 =
         if (Platform.is_windows)
           bootstrap_directory(cygwin_root, "CYGWIN_ROOT", "cygwin.root", "Cygwin root")
         else ""
 
       if (Platform.is_windows) Cygwin.init(isabelle_root1, cygwin_root1)
 
       def set_cygwin_root()
       {
         if (Platform.is_windows)
           _settings = Some(_settings.getOrElse(Map.empty) + ("CYGWIN_ROOT" -> cygwin_root1))
       }
 
       set_cygwin_root()
 
       def default(env: Map[String, String], entry: (String, String)): Map[String, String] =
         if (env.isDefinedAt(entry._1) || entry._2 == "") env
         else env + entry
 
       val env =
       {
         val temp_windows =
         {
           val temp = if (Platform.is_windows) System.getenv("TEMP") else null
           if (temp != null && temp.contains('\\')) temp else ""
         }
         val user_home = System.getProperty("user.home", "")
         val isabelle_app = System.getProperty("isabelle.app", "")
 
         default(
           default(
             default(sys.env + ("ISABELLE_JDK_HOME" -> File.standard_path(jdk_home())),
               "TEMP_WINDOWS" -> temp_windows),
             "HOME" -> user_home),
           "ISABELLE_APP" -> "true")
       }
 
       val settings =
       {
         val dump = JFile.createTempFile("settings", null)
         dump.deleteOnExit
         try {
           val cmd1 =
             if (Platform.is_windows)
               List(cygwin_root1 + "\\bin\\bash", "-l",
                 File.standard_path(isabelle_root1 + "\\bin\\isabelle"))
             else
               List(isabelle_root1 + "/bin/isabelle")
           val cmd = cmd1 ::: List("getenv", "-d", dump.toString)
 
           val (output, rc) = process_output(process(cmd, env = env, redirect = true))
           if (rc != 0) error(output)
 
           val entries =
             (for (entry <- File.read(dump).split("\u0000") if entry != "") yield {
               val i = entry.indexOf('=')
               if (i <= 0) entry -> ""
               else entry.substring(0, i) -> entry.substring(i + 1)
             }).toMap
           entries + ("PATH" -> entries("PATH_JVM")) - "PATH_JVM"
         }
         finally { dump.delete }
       }
       _settings = Some(settings)
       set_cygwin_root()
 
       val variable = "ISABELLE_SCALA_SERVICES"
       val services =
         for (name <- space_explode(':', settings.getOrElse(variable, getenv_error(variable))))
         yield {
           def err(msg: String): Nothing =
             error("Bad entry " + quote(name) + " in " + variable + "\n" + msg)
           try {
             Class.forName(name).asInstanceOf[Class[Service]]
               .getDeclaredConstructor().newInstance()
           }
           catch {
             case _: ClassNotFoundException => err("Class not found")
             case exn: Throwable => err(Exn.message(exn))
           }
         }
       _services = Some(services)
     }
   }
 
 
   /* getenv */
 
   private def getenv_error(name: String): Nothing =
     error("Undefined Isabelle environment variable: " + quote(name))
 
   def getenv(name: String, env: Map[String, String] = settings()): String =
     env.getOrElse(name, "")
 
   def getenv_strict(name: String, env: Map[String, String] = settings()): String =
     proper_string(getenv(name, env)) getOrElse
       error("Undefined Isabelle environment variable: " + quote(name))
 
   def cygwin_root(): String = getenv_strict("CYGWIN_ROOT")
 
   def isabelle_id(): String =
     proper_string(getenv("ISABELLE_ID")) getOrElse
       Mercurial.repository(Path.explode("~~")).parent()
 
 
 
   /** file-system operations **/
 
   /* permissions */
 
   def chmod(arg: String, path: Path): Unit =
     bash("chmod " + arg + " " + File.bash_path(path)).check
 
   def chown(arg: String, path: Path): Unit =
     bash("chown " + arg + " " + File.bash_path(path)).check
 
 
   /* directories */
 
   def mkdirs(path: Path): Unit =
     if (!path.is_dir) {
       bash("perl -e \"use File::Path make_path; make_path('" + File.standard_path(path) + "');\"")
       if (!path.is_dir) error("Failed to create directory: " + quote(File.platform_path(path)))
     }
 
   def copy_dir(dir1: Path, dir2: Path): Unit =
     bash("cp -a " + File.bash_path(dir1) + " " + File.bash_path(dir2)).check
 
 
   /* tmp files */
 
   def isabelle_tmp_prefix(): JFile =
   {
     val path = Path.explode("$ISABELLE_TMP_PREFIX")
     path.file.mkdirs  // low-level mkdirs
     File.platform_file(path)
   }
 
   def tmp_file(name: String, ext: String = "", base_dir: JFile = isabelle_tmp_prefix()): JFile =
   {
     val suffix = if (ext == "") "" else "." + ext
     val file = Files.createTempFile(base_dir.toPath, name, suffix).toFile
     file.deleteOnExit
     file
   }
 
   def with_tmp_file[A](name: String, ext: String = "")(body: Path => A): A =
   {
     val file = tmp_file(name, ext)
     try { body(File.path(file)) } finally { file.delete }
   }
 
 
   /* tmp dirs */
 
   def rm_tree(root: Path): Unit = rm_tree(root.file)
 
   def rm_tree(root: JFile)
   {
     root.delete
     if (root.isDirectory) {
       Files.walkFileTree(root.toPath,
         new SimpleFileVisitor[JPath] {
           override def visitFile(file: JPath, attrs: BasicFileAttributes): FileVisitResult =
           {
             try { Files.deleteIfExists(file) }
             catch { case _: IOException => }
             FileVisitResult.CONTINUE
           }
 
           override def postVisitDirectory(dir: JPath, e: IOException): FileVisitResult =
           {
             if (e == null) {
               try { Files.deleteIfExists(dir) }
               catch { case _: IOException => }
               FileVisitResult.CONTINUE
             }
             else throw e
           }
         }
       )
     }
   }
 
   def tmp_dir(name: String, base_dir: JFile = isabelle_tmp_prefix()): JFile =
   {
     val dir = Files.createTempDirectory(base_dir.toPath, name).toFile
     dir.deleteOnExit
     dir
   }
 
   def with_tmp_dir[A](name: String)(body: Path => A): A =
   {
     val dir = tmp_dir(name)
     try { body(File.path(dir)) } finally { rm_tree(dir) }
   }
 
 
   /* quasi-atomic update of directory */
 
   def update_directory(dir: Path, f: Path => Unit)
   {
     val new_dir = dir.ext("new")
     val old_dir = dir.ext("old")
 
     rm_tree(new_dir)
     rm_tree(old_dir)
 
     f(new_dir)
 
     if (dir.is_dir) File.move(dir, old_dir)
     File.move(new_dir, dir)
     rm_tree(old_dir)
   }
 
 
 
   /** external processes **/
 
   /* raw process */
 
   def process(command_line: List[String],
     cwd: JFile = null,
     env: Map[String, String] = settings(),
     redirect: Boolean = false): Process =
   {
     val proc = new ProcessBuilder
     proc.command(command_line:_*)  // fragile on Windows
     if (cwd != null) proc.directory(cwd)
     if (env != null) {
       proc.environment.clear
       for ((x, y) <- env) proc.environment.put(x, y)
     }
     proc.redirectErrorStream(redirect)
     proc.start
   }
 
   def process_output(proc: Process): (String, Int) =
   {
     proc.getOutputStream.close
 
     val output = File.read_stream(proc.getInputStream)
     val rc =
       try { proc.waitFor }
       finally {
         proc.getInputStream.close
         proc.getErrorStream.close
         proc.destroy
         Exn.Interrupt.dispose()
       }
     (output, rc)
   }
 
   def kill(signal: String, group_pid: String): (String, Int) =
   {
     val bash =
       if (Platform.is_windows) List(cygwin_root() + "\\bin\\bash.exe")
       else List("/usr/bin/env", "bash")
     process_output(process(bash ::: List("-c", "kill -" + signal + " -" + group_pid)))
   }
 
 
   /* GNU bash */
 
   def bash(script: String,
     cwd: JFile = null,
     env: Map[String, String] = settings(),
     redirect: Boolean = false,
     progress_stdout: String => Unit = (_: String) => (),
     progress_stderr: String => Unit = (_: String) => (),
-    progress_limit: Option[Long] = None,
     strict: Boolean = true,
     cleanup: () => Unit = () => ()): Process_Result =
   {
     Bash.process(script, cwd = cwd, env = env, redirect = redirect, cleanup = cleanup).
-      result(progress_stdout, progress_stderr, progress_limit, strict)
+      result(progress_stdout, progress_stderr, strict)
   }
 
   def jconsole(): Process_Result =
     bash("isabelle_jdk jconsole " + java.lang.ProcessHandle.current().pid).check
 
   private lazy val gnutar_check: Boolean =
     try { bash("tar --version").check.out.containsSlice("GNU tar") || error("") }
     catch { case ERROR(_) => false }
 
   def gnutar(
     args: String,
     dir: Path = Path.current,
     original_owner: Boolean = false,
     redirect: Boolean = false): Process_Result =
   {
     val options =
       (if (dir.is_current) "" else "-C " + File.bash_path(dir) + " ") +
       (if (original_owner) "" else "--owner=root --group=staff ")
 
     if (gnutar_check) bash("tar " + options + args, redirect = redirect)
     else error("Expected to find GNU tar executable")
   }
 
   def hostname(): String = bash("hostname -s").check.out
 
   def open(arg: String): Unit =
     bash("exec \"$ISABELLE_OPEN\" " + Bash.string(arg) + " >/dev/null 2>/dev/null &")
 
   def pdf_viewer(arg: Path): Unit =
     bash("exec \"$PDF_VIEWER\" " + File.bash_path(arg) + " >/dev/null 2>/dev/null &")
 
   def export_isabelle_identifier(isabelle_identifier: String): String =
     if (isabelle_identifier == "") ""
     else "export ISABELLE_IDENTIFIER=" + Bash.string(isabelle_identifier) + "\n"
 
 
 
   /** Isabelle resources **/
 
   /* repository clone with Admin */
 
   def admin(): Boolean = Path.explode("~~/Admin").is_dir
 
 
   /* components */
 
   def components(): List[Path] =
     Path.split(getenv_strict("ISABELLE_COMPONENTS"))
 
 
   /* default logic */
 
   def default_logic(args: String*): String =
   {
     args.find(_ != "") match {
       case Some(logic) => logic
       case None => Isabelle_System.getenv_strict("ISABELLE_LOGIC")
     }
   }
 }