The FreeBSD directory hierarchy is fundamental to obtaining an overall understanding of the system. The most important directory is root or, “/”. 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 other file systems that are mounted during the transition to multi-user operation.
A mount point is a directory where additional file systems
can be grafted onto a parent file system (usually the root file
system). This is further described in
Section 4.6, “Disk Organization”. Standard mount points
include /usr/, /var/,
/tmp/, /mnt/, and
/cdrom/. These directories are usually
referenced to entries in /etc/fstab. This
file is a table of various file systems and mount points and is
read by the system. Most of the file systems in
/etc/fstab are mounted automatically at
boot time from the script rc(8) unless their entry includes
noauto. Details can be found in
Section 4.7.1, “The fstab File”.
A complete description of the file system hierarchy is available in hier(7). The following table provides a brief overview of the most common directories.
| 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 boot configuration files. Refer to loader.conf(5) for details. |
/dev/ | Device nodes. Refer to intro(4) for details. |
/etc/ | System configuration files and scripts. |
/etc/defaults/ | Default system configuration files. Refer to rc(8) for details. |
/etc/mail/ | Configuration files for mail transport agents such as sendmail(8). |
/etc/namedb/ | named(8) configuration files. |
/etc/periodic/ | Scripts that run daily, weekly, and monthly, via cron(8). Refer to periodic(8) for details. |
/etc/ppp/ | ppp(8) configuration files. |
/mnt/ | Empty directory commonly used by system administrators as a temporary mount point. |
/proc/ | Process file system. Refer to procfs(5), mount_procfs(8) for details. |
/rescue/ | Statically linked programs for emergency recovery as described in rescue(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 which are usually
not preserved across a system
reboot. A memory-based file system is often mounted
at /tmp. This can be automated
using the tmpmfs-related variables of rc.conf(5)
or with an entry in /etc/fstab;
refer to mdmfs(8) for details. |
/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 and system utilities executed by other programs. |
/usr/local/ | Local executables and libraries. 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/. |
/usr/obj/ | Architecture-specific target tree produced by
building the /usr/src
tree. |
/usr/ports/ | The FreeBSD Ports Collection (optional). |
/usr/sbin/ | System daemons and 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 using the varmfs-related variables in
rc.conf(5) or with an entry in
/etc/fstab; refer to
mdmfs(8) for details. |
/var/log/ | Miscellaneous system log files. |
/var/mail/ | User mailbox files. |
/var/spool/ | Miscellaneous printer and mail system spooling directories. |
/var/tmp/ | Temporary files which are usually preserved
across a system reboot, unless
/var is a
memory-based file system. |
/var/yp/ | NIS maps. |
All FreeBSD documents are available for download at http://ftp.FreeBSD.org/pub/FreeBSD/doc/
Questions that are not answered by the
documentation may be
sent to <[email protected]>.
Send questions about this document to <[email protected]>.