diff --git a/init/cron.sh b/init/cron.sh
index 72825be..563ced8 100755
--- a/init/cron.sh
+++ b/init/cron.sh
@@ -9,7 +9,8 @@ if [ "$BUILDFREQ" == "" ]; then
 fi
 
 # Run the pull script regularly
-echo "*/$BUILDFREQ * * * * /aux/pull-n-build.sh" >> /var/spool/cron/crontabs/root
+cmd="$BUILDFREQ * * * * /aux/pull-n-build.sh"
+grep "$cmd" /var/spool/cron/crontabs/root || echo "$cmd" >> /var/spool/cron/crontabs/root
 
 # start cron daemon (goes into background)
 crond