Disk persistence.
File-system abstraction.
Return the current directory.
Create a directory.
Remove a file or directory (even if non-empty).
rec_files dir is the list of files recursively present in dir and all of its sub-directories. Return filenames prefixed by dir.
rec_files dir
dir
Read the contents of a file using mmap.
Write some contents to a new file.
Same as Config but gives more control on the file hierarchy.
Config
dir root is the sub-directory to look for the keys.
dir root
Convert a key to a filename.
Convert a filename to a key.