@@ -537,6 +537,29 @@ If you use STDIN or specify a `URL`, the system places the contents into a

 file called `Dockerfile`, and any `-f`, `--file` option is ignored. In this 

 scenario, there is no context.

+### Return code

+

+On a successful build, a return code of success `0` will be returned.

+When the build fails, a non-zero failure code will be returned.

+

+There should be informational output of the reason for failure output

+to `STDERR`:

+

+```

+$ docker build -t fail .

+Sending build context to Docker daemon 2.048 kB

+Sending build context to Docker daemon

+Step 0 : FROM busybox

+ ---> 4986bf8c1536

+Step 1 : RUN exit 13

+ ---> Running in e26670ec7a0a

+INFO[0000] The command [/bin/sh -c exit 13] returned a non-zero code: 13

+$ echo $?

+1

+```

+

+### .dockerignore file

+

 If a file named `.dockerignore` exists in the root of `PATH` then it

 is interpreted as a newline-separated list of exclusion patterns.

 Exclusion patterns match files or directories relative to `PATH` that