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 4.5. 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 4.6.1.
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 configuration files. Refer to named(8) for details. |
| /etc/periodic/ | Scripts that run daily, weekly, and monthly, via cron(8). Refer to periodic(8) for details. |
| /etc/ppp/ | ppp configuration files as described in ppp(8). |
| /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/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 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. |