(os/stat path &opt tab|key)
Gets information about a file or directory. Returns a table If the
third argument is a keyword, returns only that information from stat.
If the file or directory does not exist, returns nil. The keys are
:dev - the device that the file is on
:mode - the type of file, one of :file, :directory, :block,
:character, :fifo, :socket, :link, or :other
:int-permissions - A Unix permission integer like 8r744
:permissions - A Unix permission string like "rwxr--r--"
:uid - File uid
:gid - File gid
:nlink - number of links to file
:rdev - Real device of file. 0 on windows.
:size - size of file in bytes
:blocks - number of blocks in file. 0 on windows
:blocksize - size of blocks in file. 0 on windows
:accessed - timestamp when file last accessed
:changed - timestamp when file last changed (permissions changed)
:modified - timestamp when file last modified (content changed)