update burn_io.sh

Signed-off-by: Liu, Xiaopeng (133) <[email protected]>

Author: Liu, Xiaopeng (133)

chaosaws/ec2_os/scripts/burn_io.sh

@@ -16,7 +16,7 @@ timeout $duration /tmp/loop.sh
 # done &
 
 ret=$?
-if [ $ret -eq 0 || $ret -eq 124 ]; then
+if [[ $ret -eq 0 || $ret -eq 124 ]]; then
     echo "experiment burnio -> <$instance_id>: success"
 else
     echo "experiment brunio -> <$instance_id>: fail"