DISKFREE disk free space
returns disk free space in bytes
example: diskfree('/')
Ref: https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/io/File.html#getUsableSpace()
function freebytes = diskfree(d) arguments d (1,1) string {mustBeFolder} end freebytes = java.io.File(d).getUsableSpace; end