Document the new environment variable newline handling in my_init

Changelog.md

@@ -2,6 +2,14 @@
 
  * Upgraded to Ubuntu 14.04 (Trusty). We will no longer release images based on 12.04.
    Thanks to contributions by mpeterson, Paul Jimenez, Santiago M. Mola and Kingdon Barrett.
+ * Fixed a problem with my_init not correctly passing child processes' exit status. Fixes GH-45.
+ * When reading environment variables from /etc/container_environment, the trailing newline (if any) is ignored. This makes commands like this work, without unintentially adding a newline to the environment variable value:
+
+        echo my_value > /etc/container_environment/FOO
+
+   If you intended on adding a newline to the value, ensure you have *two* trailing newlines:
+
+        echo -e "my_value\n" > /etc/container_environment/FOO
 
 ## 0.9.9 (release date: 2014-03-25)
 

README.md

@@ -227,7 +227,7 @@ During startup, before running any [startup scripts](#running_startup_scripts),
 
 For example, here's how you can define an environment variable from your Dockerfile:
 
-    RUN echo -n Apachai Hopachai > /etc/container_environment/MY_NAME
+    RUN echo Apachai Hopachai > /etc/container_environment/MY_NAME
 
 You can verify that it works, as follows:
 
@@ -237,6 +237,12 @@ You can verify that it works, as follows:
     # echo $MY_NAME
     Apachai Hopachai
 
+**Handling newlines**
+
+If you've looked carefully, you'll notice that the 'echo' command actually prints a newline. Why does $MY_NAME not contain a newline then? It's because `my_init` strips the trailing newline, if any. If you intended on the value having a newline, you should add *another* newline, like this:
+
+    RUN echo -e "Apachai Hopachai\n" > /etc/container_environment/MY_NAME
+
 <a name="envvar_dumps"></a>
 #### Environment variable dumps