Despite being hidden, the files / directories etc. are fully accessible to clients who know what names to actually use.
Items will be hidden if their names contain the string given by hide_file, or if they match the regular expression specified by hide_file.
Note that vsftpd's regular expression matching code is a simple implementation which is a subset of full regular expression functionality. Example: hide_file={*.mp3,.hidden,hide*,h?}
default=none