allow empty perfdata

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