This is an archive of past FreeBSD releases; it's part of the FreeBSD Documentation Archive.
The FreeBSD 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. Standard mount points include /usr, /var, /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. Consult the fstab(5) manual page for more information on the format of the /etc/fstab file and the options it contains.
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.
| Directory | Description |
|---|---|
| / | 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. |
| /stand/ | Programs used in a standalone environment. |
| /tmp/ | Temporary files, usually a mfs(8) memory-based file system (the contents of /tmp are usually NOT preserved across a system reboot). |
| /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. Also used as the default destination for the FreeBSD ports framework. Within /usr/local, the general layout sketched out by hier(7) for /usr should be used. Exceptions are the man directory, which is directly under /usr/local rather than under /usr/local/share, and the ports documentation is in share/doc/port. |
| /usr/obj/ | Architecture-specific target tree produced by building the /usr/src tree. |
| /usr/ports | The FreeBSD ports collection (optional). |
| /usr/sbin/ | System daemons & system utilities (executed by users). |
| /usr/share/ | Architecture-independent files. |
| /usr/src/ | BSD and/or local source files. |
| /usr/X11R6/ | X11R6 distribution executables, libraries, etc (optional). |
| /var/ | Multi-purpose log, temporary, transient, and spool files. |
| /var/log/ | Miscellaneous system log files. |
| /var/mail/ | User mailbox files. |
| /var/spool/ | Miscellaneous printer and mail system spooling directories. |
| /var/tmp/ | Temporary files that are kept between system reboots. |
| /var/yp | NIS maps. |
This, and other documents, can be downloaded from ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/.
For questions about FreeBSD, read the documentation before contacting <questions@FreeBSD.org>.
For questions about this documentation, e-mail <doc@FreeBSD.org>.