diff --git a/gmsh_interop/runner.py b/gmsh_interop/runner.py
index 1fdc6cdaf6db871a472583d22530b41a4a1a3ac5..9ef66e1647931670ebd8a258442bfccff4ac94f4 100644
--- a/gmsh_interop/runner.py
+++ b/gmsh_interop/runner.py
@@ -125,7 +125,8 @@ class GmshRunner(object):
             incomplete_elements=None, other_options=[],
             extension="geo", gmsh_executable="gmsh",
             output_file_name="output.msh",
-            target_unit=None):
+            target_unit=None,
+            save_tmp_files_in=None):
         if isinstance(source, str):
             from warnings import warn
             warn("passing a string as 'source' is deprecated--use "
@@ -147,6 +148,7 @@ class GmshRunner(object):
         self.other_options = other_options
         self.gmsh_executable = gmsh_executable
         self.output_file_name = output_file_name
+        self.save_tmp_files_in = save_tmp_files_in
         self.target_unit = target_unit.upper()
 
         if self.dimensions not in [1, 2, 3, None]:
@@ -167,7 +169,9 @@ class GmshRunner(object):
         from pytools.prefork import call_capture_output
         retcode, stdout, stderr = call_capture_output(cmdline)
 
-        version = stderr.decode().strip()
+        # stderr can contain irregular info
+        import re
+        version = re.search(r'[0-9]+.[0-9]+.[0-9]+', stderr.decode().strip()).group()
         return LooseVersion(version)
 
     def __enter__(self):
@@ -276,6 +280,36 @@ class GmshRunner(object):
 
             self.output_file = open(output_file_name, "r")
 
+            if self.save_tmp_files_in:
+                import shutil, errno
+                try:
+                    shutil.copytree(working_dir, self.save_tmp_files_in)
+                except FileExistsError as exc:
+                    import select, sys
+                    print("%s exists! Overwrite? (Y/N, will default to Y in 10sec)."
+                            % self.save_tmp_files_in)
+                    decision = None
+                    while not decision:
+                        i, o, e = select.select([sys.stdin], [], [], 10)
+                        if i == "N" or i == "n":
+                            decision = 0
+                        elif i == "Y" or i == "y" or not i:
+                            decision = 1
+                        else:
+                            print("Illegal input %s, please retry." % i)
+                    if decision == 0:
+                        pass
+                    else:
+                        assert decision == 1
+                        shutil.rmtree(self.save_tmp_files_in)
+                        shutil.copytree(working_dir, self.save_tmp_files_in)
+                except OSError as exc:
+                    if exc.errno == errno.ENOTDIR:
+                        shutil.copy(output_file_name,
+                                    '/'.join([self.save_tmp_files_in,
+                                              self.output_file_name]))
+                    else: raise
+
             self.temp_dir_mgr = temp_dir_mgr
             return self
         except Exception: