1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)dir.5 8.3 (Berkeley) 4/19/94 33.\" $FreeBSD: src/share/man/man5/dir.5,v 1.12.2.5 2001/12/17 11:30:13 ru Exp $ 34.\" $DragonFly: src/share/man/man5/dir.5,v 1.6 2006/02/17 19:37:10 swildner Exp $ 35.\" 36.Dd March 5, 2005 37.Dt DIR 5 38.Os 39.Sh NAME 40.Nm dir , 41.Nm dirent 42.Nd directory file format 43.Sh SYNOPSIS 44.In dirent.h 45.Sh DESCRIPTION 46Directories provide a convenient hierarchical method of grouping 47files while obscuring the underlying details of the storage medium. 48A directory file is differentiated from a plain file 49by a flag in its 50.Xr inode 5 51entry. 52It consists of records (directory entries) each of which contains 53information about a file and a pointer to the file itself. 54Directory entries may contain other directories 55as well as plain files; such nested directories are referred to as 56subdirectories. 57A hierarchy of directories and files is formed in this manner 58and is called a file system (or referred to as a file system tree). 59.\" An entry in this tree, 60.\" nested or not nested, 61.\" is a pathname. 62.Pp 63Each directory file contains two special directory entries; one is a pointer 64to the directory itself 65called dot 66.Ql .\& 67and the other a pointer to its parent directory called dot-dot 68.Ql \&.. . 69Dot and dot-dot 70are valid pathnames, however, 71the system root directory 72.Ql / , 73has no parent and dot-dot points to itself like dot. 74.Pp 75File system nodes are ordinary directory files on which has 76been grafted a file system object, such as a physical disk or a 77partitioned area of such a disk. 78(See 79.Xr mount 2 80and 81.Xr mount 8 . ) 82.Pp 83The directory entry format is defined in 84.Aq Pa sys/dirent.h . 85This file should not be included directly by applications. 86.Sh SEE ALSO 87.Xr fs 5 , 88.Xr inode 5 89.Sh HISTORY 90A 91.Nm 92file format appeared in 93.At v7 . 94.Sh BUGS 95The usage of the member d_type of struct dirent is unportable as it is 96.Dx Ns / Ns Fx Ns -specific . 97It also may fail on certain filesystems, for example the cd9660 filesystem. 98