parameter to grep event error

e.observability.md

@@ -175,7 +175,7 @@ kubectl run busybox --restart=Never --image=busybox -- notexist
 kubectl logs busybox # will bring nothing! container never started
 kubectl describe po busybox # in the events section, you'll see the error
 # also...
-kubectl get events | grep error # you'll see the error here as well
+kubectl get events | grep -i error # you'll see the error here as well
 kubectl delete po busybox --force --grace-period=0
 ```