How to hot-code-swap with erlang

One of the most famous features of erlang is hot code swap.
What we'll do is open a shell into the running process and then load the new code.

1. The application must have been launched with -name app_name flag
2. Compile your code
3. Launch an erlang shell with:
   > erl -name name_of_this_shell -remsh name_of_remote_process@remote_process_host
4. Load the new module with:
   > l(module_name).

Simple!?