diff --git a/pd/src/s_main.c b/pd/src/s_main.c
index 8b95328019b7e49db882a7d3a7c59adfbdd17297..807fae30f31226bce4627056ff77bf3a73de6a47 100644
--- a/pd/src/s_main.c
+++ b/pd/src/s_main.c
@@ -426,7 +426,8 @@ static char *(usagemessage[]) = {
 "-font-weight <name>-- specify default font weight (normal or bold)\n",
 "-verbose         -- extra printout on startup and when searching for files\n",
 "-version         -- don't run Pd; just print out which version it is \n",
-"-d <n>           -- specify debug level\n",
+"-d <n>           -- specify debug type: 1=out, 2=in, 4=linenumbers\n",
+"                      (combine by adding. e.g. -d 5 is -d 1 and -d 4)\n",
 "-noloadbang      -- suppress all loadbangs\n",
 "-stderr          -- send printout to standard error instead of GUI\n",
 "-nogui           -- suppress starting the GUI\n",