Minimal directory creation bash builtin.
Documentation for std::fs::create_dir_all states that it should not an error while trying to create the same directory concurrently:
Notable exception is made for situations where any of the directories specified in the path could not be created as it was being created concurrently. Such cases are considered to be successful. That is, calling create_dir_all concurrently from multiple threads or processes is guaranteed not to fail due to a race condition with itself.
Createdir will try to create each directory that you pass as arguments:
createdir /tmp/dir/to/create /tmp/an/another/dir/to/create
It may fail for a permission denied for instance in that case the remaining directories are not created.
On success it does not print anything. It is not an error if the directory to be created exists already.