update README.md by cleaning up command prompts

Author: SataQiu

test/images/pets/redis-installer/README.md

@@ -4,7 +4,7 @@ The image in this directory is the init container for contrib/pets/redis but for
 
 You can execute the image locally via:
 ```
-$ docker run -it k8s.gcr.io/redis-install-3.2.0:e2e --cmd --install-into=/opt --work-dir=/work-dir
+docker run -it k8s.gcr.io/redis-install-3.2.0:e2e --cmd --install-into=/opt --work-dir=/work-dir
 ```
 To share the installation with other containers mount the appropriate volumes as `--install-into` and `--work-dir`, where `install-into` is the directory to install redis into, and `work-dir` is the directory to install the user/admin supplied on-{start,change} hook scripts.
 

test/images/pets/zookeeper-installer/README.md

@@ -4,7 +4,7 @@ The image in this directory is the init container for contrib/pets/zookeeper but
 
 You can execute the image locally via:
 ```
-$ docker run -it k8s.gcr.io/zookeeper-install-3.5.0-alpha:e2e --cmd --install-into=/opt --work-dir=/work-dir
+docker run -it k8s.gcr.io/zookeeper-install-3.5.0-alpha:e2e --cmd --install-into=/opt --work-dir=/work-dir
 ```
 To share the installation with other containers mount the appropriate volumes as `--install-into` and `--work-dir`, where `install-into` is the directory to install zookeeper into, and `work-dir` is the directory to install the user/admin supplied on-{start,change} hook scripts.
 

test/images/resource-consumer/README.md

@@ -48,14 +48,14 @@ Custom metrics in Prometheus format are exposed on "/metrics" endpoint.
 
 ### CURL example
 ```console
-$ kubectl run resource-consumer --image=gcr.io/kubernetes-e2e-test-images/resource-consumer:1.4 --expose --service-overrides='{ "spec": { "type": "LoadBalancer" } }' --port 8080 --requests='cpu=500m,memory=256Mi'
-$ kubectl get services resource-consumer
+kubectl run resource-consumer --image=gcr.io/kubernetes-e2e-test-images/resource-consumer:1.4 --expose --service-overrides='{ "spec": { "type": "LoadBalancer" } }' --port 8080 --requests='cpu=500m,memory=256Mi'
+kubectl get services resource-consumer
 ```
 
 There are two IPs.  The first one is internal, while the second one is the external load-balanced IP.  Both serve port 8080. (Use second one)
 
 ```console
-$ curl --data "millicores=300&durationSec=600" http://<EXTERNAL-IP>:8080/ConsumeCPU
+curl --data "millicores=300&durationSec=600" http://<EXTERNAL-IP>:8080/ConsumeCPU
 ```
 
 300 millicores will be consumed for 600 seconds.