1 files changed, 49 insertions, 0 deletions
diff --git a/examples/customization/pwd-cd-and-system/utils.py b/examples/customization/pwd-cd-and-system/utils.py
new file mode 100644
index 000000000000..e975e8869773
--- /dev/null
+++ b/examples/customization/pwd-cd-and-system/utils.py
@@ -0,0 +1,49 @@
+"""Utility for changing directories and execution of commands in a subshell."""
+
+import os, shlex, subprocess
+
+# Store the previous working directory for the 'cd -' command.
+class Holder:
+    """Holds the _prev_dir_ class attribute for chdir() function."""
+    _prev_dir_ = None
+
+    @classmethod
+    def prev_dir(cls):
+        return cls._prev_dir_
+
+    @classmethod
+    def swap(cls, dir):
+        cls._prev_dir_ = dir
+
+def chdir(debugger, args, result, dict):
+    """Change the working directory, or cd to ${HOME}.
+    You can also issue 'cd -' to change to the previous working directory."""
+    new_dir = args.strip()
+    if not new_dir:
+        new_dir = os.path.expanduser('~')
+    elif new_dir == '-':
+        if not Holder.prev_dir():
+            # Bad directory, not changing.
+            print "bad directory, not changing"
+            return
+        else:
+            new_dir = Holder.prev_dir()
+
+    Holder.swap(os.getcwd())
+    os.chdir(new_dir)
+    print "Current working directory: %s" % os.getcwd()
+
+def system(debugger, command_line, result, dict):
+    """Execute the command (a string) in a subshell."""
+    args = shlex.split(command_line)
+    process = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    output, error = process.communicate()
+    retcode = process.poll()
+    if output and error:
+        print "stdout=>\n", output
+        print "stderr=>\n", error
+    elif output:
+        print output
+    elif error:
+        print error
+    print "retcode:", retcode