docker-build.md

@@ -30,7 +30,7 @@ Where `/path/to/ShellB3` is the absolute path to the ShellB3 repository you clon
 
 You can also replace `mk_polar2grid bin_dist clean` with any `shallbethree.sh` arguments. Note that each call to `docker run` will create a new docker container that will need to be deleted.
 
-4. Delete the docker container when complete:
+4. Delete the docker container when complete. Optionally you could include `--rm` in the original docker run command in step 3 to automatically remove the container when it exits:
 
 ```
 docker rm shellb3_centos6_build