sklangref.pdf 里倒是有一个工具，就是我想要的
createDirHier
createDirHier(
t_pathName
)
=> t/nil
Description
Creates all directories specified in the given SKILL path that do not already exist
The permissions associated with new directories are subject to the file creation mask on
systems supporting that concept. If the directory with the specified name already exists, nil
is returned. The directory names in the given SKILL path can be specified with either absolute
or relative; the SKILL path is used in the latter case.
Note: A path that is anchored to the current directory, for example, ./, ../, or ../../.., etc., is not
considered as a relative path.