fix(user-data): add fixed version of sed command to "make discovery-url"

Author: mboersma

.gitignore

@@ -62,3 +62,7 @@ contrib/ec2/cloudformation.json
 
 # GCE generated user-data
 contrib/gce/gce-user-data
+
+# user-data backup file
+contrib/coreos/user-data.orig
+

Makefile

@@ -15,6 +15,9 @@ dev-registry: check-docker
 	@echo "To configure the registry for local Deis development:"
 	@echo "    export DEIS_REGISTRY=`boot2docker ip 2>/dev/null`:5000"
 
+discovery-url:
+	sed -i .orig -e "s,# discovery: https://discovery.etcd.io/12345693838asdfasfadf13939923,discovery: $$(curl -q -w '\n' https://discovery.etcd.io/new)," contrib/coreos/user-data
+
 build: check-docker
 	@$(foreach C, $(COMPONENTS), $(MAKE) -C $(C) build ;)
 

README.md

@@ -29,7 +29,7 @@ Each time you spin up a new CoreOS cluster, you **must** provide a new [discover
 Automatically generate a fresh discovery URL with:
 
 ```console
-$ sed -i -e "s,# discovery: https://discovery.etcd.io/12345693838asdfasfadf13939923,discovery: $(curl -q -w '\n' https://discovery.etcd.io/new)," contrib/coreos/user-data
+$ sed -i .orig -e "s,# discovery: https://discovery.etcd.io/12345693838asdfasfadf13939923,discovery: $(curl -q -w '\n' https://discovery.etcd.io/new)," contrib/coreos/user-data
 ```
 
 or manually edit [contrib/coreos/user-data](contrib/coreos/user-data) and add a unique discovery URL generated from <https://discovery.etcd.io/new>.