diff -r 153ed199c0d4 -r 6cfec8029831 src/Pure/ML/ml_process.scala
--- a/src/Pure/ML/ml_process.scala	Wed Nov 13 20:21:05 2019 +0100
+++ b/src/Pure/ML/ml_process.scala	Thu Nov 14 11:35:02 2019 +0100
@@ -75,7 +75,7 @@
 
     // options
     val isabelle_process_options = Isabelle_System.tmp_file("options")
-    Isabelle_System.bash("chmod 600 " + File.bash_path(File.path(isabelle_process_options))).check
+    Isabelle_System.chmod("600", File.path(isabelle_process_options))
     File.write(isabelle_process_options, YXML.string_of_body(options.encode))
     val env_options = Map("ISABELLE_PROCESS_OPTIONS" -> File.standard_path(isabelle_process_options))
     val eval_options = if (heaps.isEmpty) Nil else List("Options.load_default ()")