Reverted r99039 and r99044. This is not what I came here for.

src/Zope2/utilities/mkzopeinstance.py

@@ -56,23 +56,31 @@ def main():
     for opt, arg in opts:
         if opt in ("-d", "--dir"):
             skeltarget = os.path.abspath(os.path.expanduser(arg))
+            if not skeltarget:
+                usage(sys.stderr, "dir must not be empty")
+                sys.exit(2)
         if opt in ("-s", "--skelsrc"):
             skelsrc = os.path.abspath(os.path.expanduser(arg))
+            if not skelsrc:
+                usage(sys.stderr, "skelsrc must not be empty")
+                sys.exit(2)
         if opt in ("-p", "--python"):
             python = os.path.abspath(os.path.expanduser(arg))
+            if not os.path.exists(python) and os.path.isfile(python):
+                usage(sys.stderr, "The Python interpreter does not exist.")
+                sys.exit(2)
         if opt in ("-h", "--help"):
             usage(sys.stdout)
             sys.exit()
         if opt in ("-u", "--user"):
+            if not arg:
+                usage(sys.stderr, "user must not be empty")
+                sys.exit(2)
             if not ":" in arg:
                 usage(sys.stderr, "user must be specified as name:password")
                 sys.exit(2)
             user, password = arg.split(":", 1)
 
-    if python is not None and not os.path.isfile(python):
-        usage(sys.stderr, "The Python interpreter does not exist.")
-        sys.exit(2)
-
     if not skeltarget:
         # interactively ask for skeltarget and initial user name/passwd.
         # cant set custom instancehome in interactive mode, we default