3.4 Directory Structure

The DragonFly directory hierarchy is fundamental to obtaining an overall understanding of the system. The most important concept to grasp is that of the root directory, ``/''. This directory is the first one mounted at boot time and it contains the base system necessary to prepare the operating system for multi-user operation. The root directory also contains mount points for every other file system that you may want to mount.

A mount point is a directory where additional file systems can be grafted onto the root file system. This is further described in Section 3.5. Standard mount points include /usr, /var, /tmp, /mnt, and /cdrom. These directories are usually referenced to entries in the file /etc/fstab. /etc/fstab is a table of various file systems and mount points for reference by the system. Most of the file systems in /etc/fstab are mounted automatically at boot time from the script rc(8) unless they contain the noauto option. Details can be found in Section 3.6.1.

A complete description of the file system hierarchy is available in hier(7). For now, a brief overview of the most common directories will suffice.

/Root directory of the file system.
/bin/User utilities fundamental to both single-user and multi-user environments.
/boot/Programs and configuration files used during operating system bootstrap.
/boot/defaults/Default bootstrapping configuration files; see loader.conf(5).
/dev/Device nodes; see intro(4).
/etc/System configuration files and scripts.
/etc/defaults/Default system configuration files; see rc(8).
/etc/mail/Configuration files for mail transport agents such as sendmail(8).
/etc/namedb/named configuration files; see named(8).
/etc/periodic/Scripts that are run daily, weekly, and monthly, via cron(8); see periodic(8).
/etc/ppp/ppp configuration files; see ppp(8).
/mnt/Empty directory commonly used by system administrators as a temporary mount point.
/proc/Process file system; see procfs(5), mount_procfs(8).
/root/Home directory for the root account.
/sbin/System programs and administration utilities fundamental to both single-user and multi-user environments.
/tmp/Temporary files. The contents of /tmp are usually NOT preserved across a system reboot. A memory-based file system is often mounted at /tmp. This can be automated with an entry in /etc/fstab; see mfs(8).
/usr/The majority of user utilities and applications.
/usr/bin/Common utilities, programming tools, and applications.
/usr/include/Standard C include files.
/usr/lib/Archive libraries.
/usr/libdata/Miscellaneous utility data files.
/usr/libexec/System daemons & system utilities (executed by other programs).
/usr/local/Local executables, libraries, etc. Within /usr/local, the general layout sketched out by hier(7) for /usr should be used. An exceptions is the man directory, which is directly under /usr/local rather than under /usr/local/share.
/usr/obj/Architecture-specific target tree produced by building the /usr/src tree.
/usr/pkgUsed as the default destination for the files installed via the pkgsrc® tree or pkgsrc packages (optional). The configuration directory is tunable, but the default location is /usr/pkg/etc.
/usr/pkg/xorg/X11R6 distribution executables, libraries, etc (optional).
/usr/pkgsrcThe pkgsrc tree for installing packages (optional).
/usr/sbin/System daemons & system utilities (executed by users).
/usr/share/Architecture-independent files.
/usr/src/BSD and/or local source files.
/var/Multi-purpose log, temporary, transient, and spool files. A memory-based file system is sometimes mounted at /var. This can be automated with an entry in /etc/fstab; see mfs(8).
/var/log/Miscellaneous system log files.
/var/mail/User mailbox files.
/var/spool/Miscellaneous printer and mail system spooling directories.
/var/tmp/Temporary files. The files are usually preserved across a system reboot, unless /var is a memory-based file system.
/var/ypNIS maps.

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