diff --git a/bin/mpd-monitor b/bin/mpd-monitor
index 8a025d2..d477c3e 100755
--- a/bin/mpd-monitor
+++ b/bin/mpd-monitor
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 # quit if another instance is already running
-if [ -n $(pidof mpc idleloop) ];then
+if [ !$(pidof mpc idleloop > /dev/null) ]; then
   echo "mpd-monitor already running"
   exit
 fi