中文譯文:檔案系統層次結構标準(FHS)(for Linux)
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wiki:https://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
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本文更新位址:http://blog.csdn.net/qq_29753285/article/details/69790931
Filesystem Hierarchy Standard (FHS)由linux基金會維護,
目前(2017-4-9),FHS的最新版本為3.0,可從http://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.pdf下載下傳
Filesystem Hierarchy Standard
Developed by Linux Foundation
Initial release 14 February 1994
Latest release 3.0 (3 June 2015)
Website Official website
The Filesystem Hierarchy Standard (FHS) defines the directory structure and directory contents in Unix-like operating systems. It is maintained by the Linux Foundation. The latest version is 3.0, released on 3 June 2015. Currently it is only used by Linux distributions.
Directory structure
In the FHS, all files and directories appear under the root directory /, even if they are stored on different physical or virtual devices. Some of these directories only exist on a particular system if certain subsystems, such as the X Window System, are installed.
Most of these directories exist in all UNIX operating systems and are generally used in much the same way; however, the descriptions here are those used specifically for the FHS, and are not considered authoritative for platforms other than Linux.
- /
Primary hierarchy root and root directory of the entire file system hierarchy.
- /bin
Essential command binaries that need to be available in single user mode; for all users, e.g., cat, ls, cp.
- /boot
Boot loader files, e.g., kernels, initrd.
- /dev
Essential device files, e.g., /dev/null.
- /etc
Host-specific system-wide configuration files
There has been controversy over the meaning of the name itself. In early versions of the UNIX Implementation Document from Bell labs, /etc is referred to as the etcetera directory, as this directory historically held everything that did not belong elsewhere (however, the FHS restricts /etc to static configuration files and may not contain binaries). Since the publication of early documentation, the directory name has been re-explained in various ways. Recent interpretations include backronyms such as "Editable Text Configuration" or "Extended Tool Chest".[5]
- /etc/opt
Configuration files for add-on packages that are stored in /opt/.
- /etc/sgml
Configuration files, such as catalogs, for software that processes SGML.
- /etc/X11
Configuration files for the X Window System, version 11.
- /etc/xml
Configuration files, such as catalogs, for software that processes XML.
- /etc/opt
- /home
Users home directories, containing saved files, personal settings, etc.
- /lib
Libraries essential for the binaries in /bin/ and /sbin/.
- /lib
Alternate format essential libraries. Such directories are optional, but if they exist, they have some requirements.
- /media
Mount points for removable media such as CD-ROMs (appeared in FHS-2.3).
- /mnt
Temporarily mounted filesystems.
- /opt
Optional application software packages.
- /proc
Virtual filesystem providing process and kernel information as files. In Linux, corresponds to a procfs mount.
- /root
Home directory for the root user.
- /run
Run-time variable data: Information about the running system since last boot, e.g., currently logged-in users and running daemons.
- /sbin
Essential system binaries, e.g., fsck, init, route.
- /srv
Site-specific data served by this system, such as data and scripts for web servers, data offered by FTP servers, and repositories for version control systems.
- /sys
Contains information about the devices connected to the computer.
- /tmp
Temporary files (see also /var/tmp). Often not preserved between system reboots, and may be severely size restricted.
- /usr
Secondary hierarchy for read-only user data; contains the majority of (multi-)user utilities and applications.
- /usr/bin
Non-essential command binaries (not needed in single user mode); for all users.
- /usr/include
Standard include files.
- /usr/lib
Libraries for the binaries in /usr/bin/ and /usr/sbin/.
- /usr/lib
Alternate format libraries (optional).
- /usr/local
Tertiary hierarchy for local data, specific to this host. Typically has further subdirectories, e.g., bin/, lib/, share/.
- /usr/sbin
Non-essential system binaries, e.g., daemons for various network-services.
- /usr/share
Architecture-independent (shared) data.
- /usr/src
Source code, e.g., the kernel source code with its header files.
- /usr/X11R6
X Window System, Version 11, Release 6 (up to FHS-2.3, optional).
- /usr/bin
- /var
Variable files—files whose content is expected to continually change during normal operation of the system—such as logs, spool files, and temporary e-mail files.
- /var/cache
Application cache data. Such data are locally generated as a result of time-consuming I/O or calculation. The application must be able to regenerate or restore the data. The cached files can be deleted without loss of data.
- /var/lib
State information. Persistent data modified by programs as they run, e.g., databases, packaging system metadata, etc.
- /var/lock
Lock files. Files keeping track of resources currently in use.
- /var/log
Log files. Various logs.
- /var/mail
Mailbox files. In some distributions, these files may be located in the deprecated /var/spool/mail.
- /var/opt
Variable data from add-on packages that are stored in /opt/.
- /var/run
Run-time variable data. This directory contains system information data describing the system since it was booted.
In FHS 3.0, /var/run is replaced by /run; a system should either continue to provide a /var/run directory, or provide a symbolic link from /var/run to /run, for backwards compatibility.[10]
- /var/spool
Spool for tasks waiting to be processed, e.g., print queues and outgoing mail queue.
- /var/spool/mail
Deprecated location for users mailboxes.
- /var/spool/mail
- /var/tmp
Temporary files to be preserved between reboots.
- /var/cache
- /bin
FHS compliance
Most Linux distributions follow the Filesystem Hierarchy Standard and declare it their own policy to maintain FHS compliance.GoboLinux and NixOS provide examples of intentionally non-compliant filesystem implementations.
Some distributions that generally follow the standard deviate from it in some areas. Common deviations include:
- Modern Linux distributions include a /sys directory as a virtual filesystem (sysfs, comparable to /proc, which is a procfs), which stores and allows modification of the devices connected to the system,[18] whereas many traditional UNIX and Unix-like operating systems use /sys as a symbolic link to the kernel source tree.
- Many modern UNIX systems (like FreeBSD via its ports system) install third party packages into /usr/local while keeping code considered part of the operating system in /usr.
- Some Linux distributions no longer differentiate between /lib versus /usr/lib and have /lib symlinked to /usr/lib.
- Some Linux distributions no longer differentiate between /bin versus /usr/bin and /sbin versus /usr/sbin. They symlink /bin to /usr/bin and /sbin to /usr/sbin. And /usr/sbin may get symlinked to /usr/bin.
Modern Linux distributions include a /run directory as a temporary filesystem (tmpfs) which stores volatile runtime data, following the FHS version 3.0. According to the FHS version 2.3, such data were stored in /var/run but this was a problem in some cases because this directory is not always available at early boot. As a result, these programs have had to resort to trickery, such as using /dev/.udev, /dev/.mdadm, /dev/.systemd or /dev/.mount directories, even though the device directory isn’t intended for such data. Among other advantages, this makes the system easier to use normally with the root filesystem mounted read-only. For example, below are the changes Debian made in its 2013 Wheezy release:
- /dev/.* → /run/*
- /dev/shm → /run/shm
- /dev/shm/* → /run/*
- /etc/* (writeable files) → /run/*
- /lib/init/rw → /run
- /var/lock → /run/lock
- /var/run → /run
- /tmp → /run/tmp
History
When the FHS was created as the FSSTND (short for “Filesystem Standard”), other UNIX and Unix-like operating systems already had their own standards. Notable examples are these: the hier(7) description of file system layout, which has existed since the release of Version 7 Unix (in 1979); the SunOS filesystem(7) and its successor, the Solaris filesystem(5).
Release history
legend | Version | Release Date | Notes |
---|---|---|---|
older version | 1 | 1994/2/14 | FSSTND |
older version | 1.1 | 1994/10/9 | FSSTND |
older version | 1.2 | 1995/3/28 | FSSTND |
older version | 2 | 1997/10/26 | FHS 2.0 is the direct successor for FSSTND 1.2. Name of the standard was changed to Filesystem Hierarchy Standard. |
older version | 2.1 | 2000/4/12 | FHS |
older version | 2.2 | 2001/5/23 | FHS |
still supported | 2.3 | 2004/1/29 | FHS |
latest version | 3 | 2015/5/18 | FHS |
See also
Unix directory structure
Intel Binary Compatibility Standard (iBCS)
hier(7)– Linux Programmer’s Manual – Overview, Conventions and Miscellanea