Create Deep Directory
From ErlangCentral Wiki
You want to be able to create a directory without having to verify each parent element of the directory exists.
The ensure_dir function of the filelib module checks that all parent directories for a given directory name exists, creating any elements if needed.
1> filelib:ensure_dir("/this/path/will/soon/exist"). ok
This is one area where Erlang makes it very easy. This useful library module helps us avoid a lot of repetitive boilerplate code.