fix some incorrect symbols before executing command

Signed-off-by: lixiaobing10051267 <li.xiaobing1@zte.com.cn>

docs/examples/apt-cacher-ng.md

@@ -102,7 +102,7 @@ instruction, and the image we built to run the service:
 
     $ docker run --rm -t -i --volumes-from test_apt_cacher_ng eg_apt_cacher_ng bash
 
-    $$ /usr/lib/apt-cacher-ng/distkill.pl
+    root@f38c87f2a42d:/# /usr/lib/apt-cacher-ng/distkill.pl
     Scanning /var/cache/apt-cacher-ng, please wait...
     Found distributions:
     bla, taggedcount: 0

docs/examples/running_ssh_service.md

@@ -57,7 +57,7 @@ Docker daemon host:
 
     $ ssh root@192.168.1.2 -p 49154
     # The password is ``screencast``.
-    $$
+    root@f38c87f2a42d:/#
 
 ## Environment variables
 

docs/reference/commandline/attach.md

@@ -119,7 +119,7 @@ process is returned by the `docker attach` command to its caller too:
     $ docker run --name test -d -it debian
     275c44472aebd77c926d4527885bb09f2f6db21d878c75f0a1c212c03d3bcfab
     $ docker attach test
-    $$ exit 13
+    root@f38c87f2a42d:/# exit 13
     exit
     $ echo $?
     13

docs/reference/commandline/run.md

@@ -546,7 +546,7 @@ more `--add-host` flags. This example adds a static address for a host named
 `docker`:
 
     $ docker run --add-host=docker:10.180.0.1 --rm -it debian
-    $$ ping docker
+    root@f38c87f2a42d:/# ping docker
     PING docker (10.180.0.1): 48 data bytes
     56 bytes from 10.180.0.1: icmp_seq=0 ttl=254 time=7.600 ms
     56 bytes from 10.180.0.1: icmp_seq=1 ttl=254 time=30.705 ms

docs/security/https/README.md

@@ -14,20 +14,20 @@ At this point, it has to be a manual thing, and I've been running it in boot2doc
 My process is as following:
 
     $ boot2docker ssh
-    $$ git clone https://github.com/docker/docker
-    $$ cd docker/docs/articles/https
-    $$ make cert
+    root@boot2docker:/# git clone https://github.com/docker/docker
+    root@boot2docker:/# cd docker/docs/articles/https
+    root@boot2docker:/# make cert
 
 lots of things to see and manually answer, as openssl wants to be interactive
 
 **NOTE:** make sure you enter the hostname (`boot2docker` in my case) when prompted for `Computer Name`)
 
-    $$ sudo make run
+    root@boot2docker:/# sudo make run
 
 Start another terminal:
 
     $ boot2docker ssh
-    $$ cd docker/docs/articles/https
-    $$ make client
+    root@boot2docker:/# cd docker/docs/articles/https
+    root@boot2docker:/# make client
 
 The last will connect first with `--tls` and then with `--tlsverify`, both should succeed.

docs/userguide/networking/default_network/configure-dns.md

@@ -19,7 +19,7 @@ automatically when you install Docker.
 How can Docker supply each container with a hostname and DNS configuration, without having to build a custom image with the hostname written inside?  Its trick is to overlay three crucial `/etc` files inside the container with virtual files where it can write fresh information.  You can see this by running `mount` inside a container:
 
 ```
-$$ mount
+root@f38c87f2a42d:/# mount
 
 ...
 /dev/disk/by-uuid/1fec...ebdf on /etc/hostname type ext4 ...

docs/userguide/networking/default_network/custom-docker0.md

@@ -45,7 +45,7 @@ Finally, the `docker0` Ethernet bridge settings are used every time you create a
 
 $ docker run -i -t --rm base /bin/bash
 
-$$ ip addr show eth0
+root@f38c87f2a42d:/# ip addr show eth0
 
 24: eth0: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
     link/ether 32:6f:e0:35:57:91 brd ff:ff:ff:ff:ff:ff
@@ -54,12 +54,12 @@ $$ ip addr show eth0
     inet6 fe80::306f:e0ff:fe35:5791/64 scope link
        valid_lft forever preferred_lft forever
 
-$$ ip route
+root@f38c87f2a42d:/# ip route
 
 default via 172.17.42.1 dev eth0
 172.17.0.0/16 dev eth0  proto kernel  scope link  src 172.17.0.3
 
-$$ exit
+root@f38c87f2a42d:/# exit
 ```
 
 Remember that the Docker host will not be willing to forward container packets out on to the Internet unless its `ip_forward` system setting is `1` -- see the section on [Communicating to the outside world](container-communication.md#communicating-to-the-outside-world) for details.