diff --git a/icinga-cli.sh b/icinga-cli.sh
index f8ccc9b7cfe12bce82f6dcd8fe7b8b391ff6df32..87c2019013ea161fb7110287e8d0d25b4c0ed854 100755
--- a/icinga-cli.sh
+++ b/icinga-cli.sh
@@ -370,7 +370,7 @@ function processCheck(){
       # echo -------- extracted performance data:
       # echo $outPerfdata
       # echo
-      if ! echo "$outPerfdata" | grep "=[0-9\.]*;[0-9\.]*;[0-9\.]*;[0-9\.]*;" >/dev/null; then
+      if ! test -n "$outPerfdata" && echo "$outPerfdata" | grep "=[0-9\.]*;[0-9\.]*;[0-9\.]*;[0-9\.]*;" >/dev/null; then
         _elog "ABORT - this does not look like performance data: $outPerfdata"
         exit 1
       fi