src/Pure/System/isabelle_system.scala

     if (gnutar_check) bash("tar " + options + args, redirect = redirect)
     else error("Expected to find GNU tar executable")
   }
 
   def rsync(
-    cwd: JFile = null,
     progress: Progress = new Progress,
     port: Int = SSH.default_port,
     verbose: Boolean = false,
     thorough: Boolean = false,
     prune_empty_dirs: Boolean = false,

         (if (dry_run) " --dry-run" else "") +
         (if (clean) " --delete-excluded" else "") +
         (if (list) " --list-only --no-human-readable" else "") +
         filter.map(s => " --filter=" + Bash.string(s)).mkString +
         (if (args.nonEmpty) " " + Bash.strings(args) else "")
-    progress.bash(script, cwd = cwd, echo = true)
+    progress.bash(script, echo = true)
   }
 
   def rsync_dir(target: String): String = {
     if (target.endsWith(":.") || target.endsWith("/.")) target
     else if (target.endsWith(":") || target.endsWith("/")) target + "."