--- commandline.py.orig	2012-02-29 19:24:04.000000000 +0000
+++ commandline.py	2014-01-13 11:10:34.761049148 +0000
@@ -388,6 +388,9 @@
     parser.add_option("--include-regexp", metavar=_("regular_expression"), dest="",
                       type="string", action="callback", callback=add_selection)
 
+    # Lockfile 
+    parser.add_option("--lockfile", metavar=_("lockfile"))
+
     parser.add_option("--log-fd", type="int", metavar=_("file_descriptor"),
                       dest="", action="callback",
                       callback=lambda o, s, v, p: set_log_fd(v))
--- globals.py.orig	2012-02-29 19:24:05.000000000 +0000
+++ globals.py	2014-01-13 13:53:01.317053535 +0000
@@ -234,3 +234,6 @@
 
 # Renames (--rename)
 rename = {}
+
+# Lockfile
+lockfile = None
--- duplicity.orig	2013-11-21 22:38:51.000000000 +0000
+++ duplicity	2014-01-13 14:06:06.805048671 +0000
@@ -1257,6 +1257,17 @@
     # determine what action we're performing and process command line
     action = commandline.ProcessCommandLine(sys.argv[1:])
 
+    if globals.lockfile:
+        from lockfile import FileLock
+
+        lock = FileLock(globals.lockfile)
+
+        with lock:
+            main2(action)
+    else:
+        main2(action)
+
+def main2(action):
     # The following is for starting remote debugging in Eclipse with Pydev.
     # Adjust the path to your location and version of Eclipse and Pydev.
     if globals.pydevd: