* cmdline/apt-mark:

  - show error on incorrect aguments (LP: #517917), thanks to
    Torsten Spindler

cmdline/apt-mark

@@ -82,6 +82,9 @@ if __name__ == "__main__":
     else:
         STATE_FILE=options.filename
 
+    if len(args) == 0:
+        parser.error("first argument must be 'markauto', 'unmarkauto' or 'showauto'")
+
     if args[0] == "showauto":
         show_automatic(STATE_FILE)
     else:

debian/changelog

@@ -19,6 +19,9 @@ apt (0.7.25.4) UNRELEASED; urgency=low
       http://ispras.linuxfoundation.org/index.php/ABI_compliance_checker
   * apt-pkg/deb/dpkgpm.cc:
     - fix backgrounding when dpkg runs (closes: #486222)
+  * cmdline/apt-mark:
+    - show error on incorrect aguments (LP: #517917), thanks to
+      Torsten Spindler
 
   [ Robert Collins ]
   * Change the package index Info methods to allow apt-cache policy to be