diff --git a/demos/tapemon/m.sh b/demos/tapemon/m.sh
index 1b00180..15c50a8 100755
--- a/demos/tapemon/m.sh
+++ b/demos/tapemon/m.sh
@@ -1,3 +1,5 @@
+#!/bin/sh
+
 ../../tools/build.sh tapemon
 node ../../tools/prg2bin.js -i out/tapemon_apple1.prg -o out/tapemon.0280.bin