diff -r 360621bc323e -r 8a668d0a0d10 pre-inst/pre-inst.c
--- a/pre-inst/pre-inst.c	Fri Jun 24 17:30:23 2016 +0100
+++ b/pre-inst/pre-inst.c	Wed Sep 12 17:12:06 2018 +0100
@@ -135,19 +135,18 @@
 #else
 void *
 #endif
-pre_install(const char *argv0)
+pre_install(const char *path)
 {
 #ifdef WIN32
     HANDLE retval;
 #else
     void *retval;
 #endif
-    char *path;
     razor_set_lua_loader("posix",(void (*)())luaopen_posix);
     razor_set_lua_loader("whelk",(void (*)())luaopen_whelk);
-    path=plover_get_program_directory(argv0);
 #ifdef WIN32
-    retval=(HANDLE)_beginthreadex(NULL,0,pre_install_thread,path,0,NULL);
+    retval=(HANDLE)_beginthreadex(NULL,0,pre_install_thread,(void *)path,0,
+      NULL);
 #else
     if (pre_install_thread(path))
 	retval=NULL;
@@ -344,7 +343,7 @@
  *
  * Command may refer to %INSTALL_PREFIX% which will be replaced by the
  * (first) install prefix used and/or %TEST_RESULT% which will be replaced
- * bu either "pass" or "fail" depending as to whether the request succeeded
+ * by either "pass" or "fail" depending as to whether the request succeeded
  * or not. Command may also include double quotes which will be used to
  * affect how the command is split into arguments much like a shell does.
  */
@@ -429,14 +428,14 @@
 }
 
 #ifdef WIN32
-DWORD win32_pre_install_gui(char *argv0)
+DWORD win32_pre_install_gui(char *path)
 {
     HANDLE thread;
     INITCOMMONCONTROLSEX icc={0,};
     MSG msg;
     DWORD retval;
     main_thread_id=GetCurrentThreadId();
-    thread=(HANDLE)pre_install(argv0);
+    thread=(HANDLE)pre_install(path);
     if (!thread)
 	return EXIT_FAILURE;
     icc.dwSize=sizeof(icc);
@@ -458,8 +457,19 @@
 
 int main(int argc,char **argv)
 {
-    gboolean success;
+    gboolean success,uninstall=FALSE,enable_post=FALSE;
     GError *error=NULL;
+    gchar *path=NULL;
+    GOptionContext *context;
+    GOptionEntry options[]={
+	{"path",0,0,G_OPTION_ARG_FILENAME,&path,
+	  "Repository path","path"},
+	{"uninstall",'u',0,G_OPTION_ARG_NONE,&uninstall,
+	  "Uninstall all packages",NULL},
+	{"post",0,0,G_OPTION_ARG_NONE,&enable_post,
+	  "Run command after request is processed",NULL},
+	{NULL}
+    };
 #ifdef WIN32
     /*
      * pre-inst is normally a GUI application, but rpm scripts may well
@@ -478,20 +488,38 @@
     }
 #endif
     plover_exception_handler_init();
-    if (argc>1 && !strcmp(argv[1],"-u"))
+    context=g_option_context_new("[command] - install the main installer");
+    g_option_context_add_main_entries(context,options,NULL);
+    g_option_context_set_description(context,
+      "If --post is specified, then the command to run and its arguments\n"
+      "should be listed at the end of the command line.\n"
+      "Command may refer to %INSTALL_PREFIX% which will be replaced by the\n"
+      "(first) install prefix used and/or %TEST_RESULT% which will be\n"
+      "replaced by either \"pass\" or \"fail\" depending as to whether the\n"
+      "request succeeded or not. Command may also include double quotes which\n"
+      "will be used to affect how the command is split into arguments much\n"
+      "like a shell does.");
+    g_option_context_set_strict_posix(context,TRUE);
+    g_option_context_set_ignore_unknown_options(context,TRUE);
+    if (!g_option_context_parse(context,&argc,&argv,&error))
     {
+	g_printerr("pre-install: %s\n",error->message);
+	g_printerr("Use \"%s --help\" for help\n",(*argv)[0]);
+	exit(1);
+    }
+    if (uninstall)
 	success=pre_uninstall();
-	argc--;
-	argv++;
+    else
+    {
+	if (!path)
+	    path=plover_get_program_directory(argv[0]);
+#ifdef WIN32
+	success=win32_pre_install_gui(path)==EXIT_SUCCESS;
+#else
+	success=!!pre_install(path);
+#endif
     }
-    else
-#ifdef WIN32
-	success=win32_pre_install_gui(argv[0])==EXIT_SUCCESS;
-#else
-	success=!!pre_install(argv[0]);
-#endif
-    if (argc>1 && !strcmp(argv[1],"--post") &&
-      !run_post(argc-1,argv+1,success,&error))
+    if (enable_post && !run_post(argc-1,argv+1,success,&error))
     {
 #ifndef WIN32
 	fprintf(stderr,"Error in post: %s\n",error->message);