DIR(5)

NAME
dir, dirent - directory file format

SYNOPSIS
#include <dirent.h>

DESCRIPTION
Directories provide a convenient hierarchical method of grouping files while obscuring the underlying details of the storage medium. A directory file is differentiated from a plain file by a flag in its inode(5) entry. It consists of records (directory entries) each of which contains information about a file and a pointer to the file itself. Directory entries may contain other directories as well as plain files; such nested directories are referred to as subdirectories. A hierarchy of directories and files is formed in this manner and is called a file system (or referred to as a file system tree).

Each directory file contains two special directory entries; one is a pointer to the directory itself called dot ‘’. and the other a pointer to its parent directory called dot-dot ‘..’. Dot and dot-dot are valid pathnames, however, the system root directory ‘/’, has no parent and dot-dot points to itself like dot.

File system nodes are ordinary directory files on which has been grafted a file system object, such as a physical disk or a partitioned area of such a disk. (See mount(2) and mount(8).)

The directory entry format is defined in <sys/dirent.h>. This file should not be included directly by applications.

SEE ALSO
fs(5), inode(5)

HISTORY
A dir file format appeared in AT&T UNIX.

BUGS
The usage of the member d_type of struct dirent is unportable as it is DragonFly/FreeBSD-specific. It also may fail on certain filesystems, for example the cd9660 filesystem.