Fix some readme and script bugs in examples (take 2).

v2: Resolve issues from comments, fix bugs in update-demo example, rename files for clarity, add turn-down steps.

v3: Add more set commands, clean up rest of env var checks.

examples/update-demo/4-rolling-update.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+# Copyright 2014 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+if [[ "${DOCKER_HUB_USER+set}" != "set" ]] ; then
+  echo "Please set DOCKER_HUB_USER to your Docker hub account"
+  exit 1
+fi
+
+NEW_IMAGE=${1:-kitten}
+TIMING=${2:-10s}
+export KUBE_REPO_ROOT=${KUBE_REPO_ROOT-$(dirname $0)/../..}
+export KUBECFG=${KUBECFG-$KUBE_REPO_ROOT/cluster/kubecfg.sh}
+
+set -x
+
+$KUBECFG -image $DOCKER_HUB_USER/update-demo:$NEW_IMAGE -u $TIMING rollingupdate update-demo