check if we got temperature from kernel

diff --git a/w1-ds18b20-influx.sh b/w1-ds18b20-influx.sh
index a3ba047..74e32bf 100755 (executable)
--- a/w1-ds18b20-influx.sh
+++ b/w1-ds18b20-influx.sh
@@ -7,7 +7,7 @@ influx=/dev/shm/temp.influx
 
 ls /sys/bus/w1/devices/w1_bus_master*/*-*/w1_slave | while read path ; do
        temp=$( cat $path | grep t= | cut -d= -f2 )
-       if [ $temp -ne 85000 ] ; then # 85 is error
+       if [ ! -z "$temp" -a $temp -ne 85000 ] ; then # 85 is error
                temp=$( echo $temp | awk '{ printf "%.3f\n", $1 / 1000 }' )
                id=$( echo $path | cut -d/ -f 7 )
                name=$( grep "^$id" id2name.txt | cut -d' ' -f2 )