file-hierarchy man page on Kali

Man page or keyword search:  
man Server   9211 pages
apropos Keyword Search (all sections)
Output format
Kali logo
[printable version]

FILE-HIERARCHY(7)		file-hierarchy		     FILE-HIERARCHY(7)

NAME
       file-hierarchy - File system hierarchy overview

DESCRIPTION
       Operating systems using the systemd(1) system and service manager are
       organized based on a file system hierarchy inspired by UNIX, more
       specifically the hierarchy described in the File System Hierarchy[1]
       specification and hier(7). This manual page describes a more minimal,
       modernized subset of these specifications that defines more strictly
       the suggestions and restrictions systemd makes on the file system
       hierarchy.

       Many of the paths described here can be queried with the systemd-
       path(1) tool.

GENERAL STRUCTURE
       /
	   The file system root. Usually writable, but this is not required.
	   Possibly a temporary file system ("tmpfs"). Not shared with other
	   hosts (unless read-only).

       /boot
	   The boot partition used for bringing up the system. On EFI systems,
	   this is possibly the EFI System Partition, also see systemd-gpt-
	   auto-generator(8). This directory is usually strictly local to the
	   host, and should be considered read-only, except when a new kernel
	   or boot loader is installed. This directory only exists on systems
	   that run on physical or emulated hardware that requires boot
	   loaders.

       /etc
	   System-specific configuration. This directory may or may not be
	   read-only. Frequently, this directory is pre-populated with
	   vendor-supplied configuration files, but applications should not
	   make assumptions about this directory being fully populated or
	   populated at all, and should fall back to defaults if configuration
	   is missing.

       /home
	   The location for normal user's home directories. Possibly shared
	   with other systems, and never read-only. This directory should only
	   be used for normal users, never for system users. This directory
	   and possibly the directories contained within it might only become
	   available or writable in late boot or even only after user
	   authentication. This directory might be placed on
	   limited-functionality network file systems, hence applications
	   should not assume the full set of file API is available on this
	   directory. Applications should generally not reference this
	   directory directly, but via the per-user $HOME environment
	   variable, or via the home directory field of the user database.

       /root
	   The home directory of the root user. The root user's home directory
	   is located outside of /home in order to make sure the root user may
	   log in even without /home being available and mounted.

       /srv
	   The place to store general server payload, managed by the
	   administrator. No restrictions are made how this directory is
	   organized internally. Generally writable, and possibly shared among
	   systems. This directory might become available or writable only
	   very late during boot.

       /tmp
	   The place for small temporary files. This directory is usually
	   mounted as a "tmpfs" instance, and should hence not be used for
	   larger files. (Use /var/tmp for larger files.) Since the directory
	   is accessible to other users of the system, it is essential that
	   this directory is only written to with the mkstemp(3), mkdtemp(3)
	   and related calls. This directory is usually flushed at boot-up.
	   Also, files that are not accessed within a certain time are usually
	   automatically deleted. If applications find the environment
	   variable $TMPDIR set, they should prefer using the directory
	   specified in it over directly referencing /tmp (see environ(7) and
	   IEEE Std 1003.1[2] for details).

RUNTIME DATA
       /run
	   A "tmpfs" file system for system packages to place runtime data in.
	   This directory is flushed on boot, and generally writable for
	   privileged programs only. Always writable.

       /run/log
	   Runtime system logs. System components may place private logs in
	   this directory. Always writable, even when /var/log might not be
	   accessible yet.

       /run/user
	   Contains per-user runtime directories, each usually individually
	   mounted "tmpfs" instances. Always writable, flushed at each reboot
	   and when the user logs out. User code should not reference this
	   directory directly, but via the $XDG_RUNTIME_DIR environment
	   variable, as documented in the XDG Base Directory Specification[3].

VENDOR-SUPPLIED OPERATING SYSTEM RESOURCES
       /usr
	   Vendor-supplied operating system resources. Usually read-only, but
	   this is not required. Possibly shared between multiple hosts. This
	   directory should not be modified by the administrator, except when
	   installing or removing vendor-supplied packages.

       /usr/bin
	   Binaries and executables for user commands that shall appear in the
	   $PATH search path. It is recommended not to place binaries in this
	   directory that are not useful for invocation from a shell (such as
	   daemon binaries); these should be placed in a subdirectory of
	   /usr/lib instead.

       /usr/include
	   C and C++ API header files of system libraries.

       /usr/lib
	   Static, private vendor data that is compatible with all
	   architectures (though not necessarily architecture-independent).
	   Note that this includes internal executables or other binaries that
	   are not regularly invoked from a shell. Such binaries may be for
	   any architecture supported by the system. Do not place public
	   libraries in this directory, use $libdir (see below), instead.

       /lib/arch-id
	   Location for placing dynamic libraries into, also called $libdir.
	   The architecture identifier to use is defined on Multiarch
	   Architecture Specifiers (Tuples)[4] list. Legacy locations of
	   $libdir are /lib, /lib64. This directory should not be used for
	   package-specific data, unless this data is architecture-dependent,
	   too. To query $libdir for the primary architecture of the system,
	   invoke:

	       # systemd-path system-library-arch

       /usr/share
	   Resources shared between multiple packages, such as documentation,
	   man pages, time zone information, fonts and other resources.
	   Usually, the precise location and format of files stored below this
	   directory is subject to specifications that ensure
	   interoperability.

       /usr/share/doc
	   Documentation for the operating system or system packages.

       /usr/share/factory/etc
	   Repository for vendor-supplied default configuration files. This
	   directory should be populated with pristine vendor versions of all
	   configuration files that may be placed in /etc. This is useful to
	   compare the local configuration of a system with vendor defaults
	   and to populate the local configuration with defaults.

       /usr/share/factory/var
	   Similar to /usr/share/factory/etc, but for vendor versions of files
	   in the variable, persistent data directory /var.

PERSISTENT VARIABLE SYSTEM DATA
       /var
	   Persistent, variable system data. Must be writable. This directory
	   might be pre-populated with vendor-supplied data, but applications
	   should be able to reconstruct necessary files and directories in
	   this subhierarchy should they be missing, as the system might start
	   up without this directory being populated. Persistency is
	   recommended, but optional, to support ephemeral systems. This
	   directory might become available or writable only very late during
	   boot. Components that are required to operate during early boot
	   hence shall not unconditionally rely on this directory.

       /var/cache
	   Persistent system cache data. System components may place
	   non-essential data in this directory. Flushing this directory
	   should have no effect on operation of programs, except for
	   increased runtimes necessary to rebuild these caches.

       /var/lib
	   Persistent system data. System components may place private data in
	   this directory.

       /var/log
	   Persistent system logs. System components may place private logs in
	   this directory, though it is recommended to do most logging via the
	   syslog(3) and sd_journal_print(3) calls.

       /var/spool
	   Persistent system spool data, such as printer or mail queues.

       /var/tmp
	   The place for larger and persistent temporary files. In contrast to
	   /tmp, this directory is usually mounted from a persistent physical
	   file system and can thus accept larger files. (Use /tmp for smaller
	   files.) This directory is generally not flushed at boot-up, but
	   time-based cleanup of files that have not been accessed for a
	   certain time is applied. The same security restrictions as with
	   /tmp apply, and hence only mkstemp(3), mkdtemp(3) or similar calls
	   should be used to make use of this directory. If applications find
	   the environment variable $TMPDIR set, they should prefer using the
	   directory specified in it over directly referencing /var/tmp (see
	   environ(7) for details).

VIRTUAL KERNEL AND API FILE SYSTEMS
       /dev
	   The root directory for device nodes. Usually, this directory is
	   mounted as a "devtmpfs" instance, but might be of a different type
	   in sandboxed/containerized setups. This directory is managed
	   jointly by the kernel and systemd-udevd(8), and should not be
	   written to by other components. A number of special purpose virtual
	   file systems might be mounted below this directory.

       /dev/shm
	   Place for POSIX shared memory segments, as created via shm_open(3).
	   This directory is flushed on boot, and is a "tmpfs" file system.
	   Since all users have write access to this directory, special care
	   should be taken to avoid name clashes and vulnerabilities. For
	   normal users, shared memory segments in this directory are usually
	   deleted when the user logs out. Usually, it is a better idea to use
	   memory mapped files in /run (for system programs) or
	   $XDG_RUNTIME_DIR (for user programs) instead of POSIX shared memory
	   segments, since these directories are not world-writable and hence
	   not vulnerable to security-sensitive name clashes.

       /proc
	   A virtual kernel file system exposing the process list and other
	   functionality. This file system is mostly an API to interface with
	   the kernel and not a place where normal files may be stored. For
	   details, see proc(5). A number of special purpose virtual file
	   systems might be mounted below this directory.

       /proc/sys
	   A hierarchy below /proc that exposes a number of kernel tunables.
	   The primary way to configure the settings in this API file tree is
	   via sysctl.d(5) files. In sandboxed/containerized setups, this
	   directory is generally mounted read-only.

       /sys
	   A virtual kernel file system exposing discovered devices and other
	   functionality. This file system is mostly an API to interface with
	   the kernel and not a place where normal files may be stored. In
	   sandboxed/containerized setups, this directory is generally mounted
	   read-only. A number of special purpose virtual file systems might
	   be mounted below this directory.

COMPATIBILITY SYMLINKS
       /bin, /sbin, /usr/sbin
	   These compatibility symlinks point to /usr/bin, ensuring that
	   scripts and binaries referencing these legacy paths correctly find
	   their binaries.

       /lib
	   This compatibility symlink points to /lib, ensuring that programs
	   referencing this legacy path correctly find their resources.

       /lib64
	   On some architecture ABIs, this compatibility symlink points to
	   $libdir, ensuring that binaries referencing this legacy path
	   correctly find their dynamic loader. This symlink only exists on
	   architectures whose ABI places the dynamic loader in this path.

       /var/run
	   This compatibility symlink points to /run, ensuring that programs
	   referencing this legacy path correctly find their runtime data.

HOME DIRECTORY
       User applications may want to place files and directories in the user's
       home directory. They should follow the following basic structure. Note
       that some of these directories are also standardized (though more
       weakly) by the XDG Base Directory Specification[3]. Additional
       locations for high-level user resources are defined by
       xdg-user-dirs[5].

       ~/.cache
	   Persistent user cache data. User programs may place non-essential
	   data in this directory. Flushing this directory should have no
	   effect on operation of programs, except for increased runtimes
	   necessary to rebuild these caches. If an application finds
	   $XDG_CACHE_HOME set, it should use the directory specified in it
	   instead of this directory.

       ~/.config
	   Application configuration and state. When a new user is created,
	   this directory will be empty or not exist at all. Applications
	   should fall back to defaults should their configuration or state in
	   this directory be missing. If an application finds $XDG_CONFIG_HOME
	   set, it should use the directory specified in it instead of this
	   directory.

       ~/.local/bin
	   Executables that shall appear in the user's $PATH search path. It
	   is recommended not to place executables in this directory that are
	   not useful for invocation from a shell; these should be placed in a
	   subdirectory of ~/.local/lib instead. Care should be taken when
	   placing architecture-dependent binaries in this place, which might
	   be problematic if the home directory is shared between multiple
	   hosts with different architectures.

       ~/.local/lib
	   Static, private vendor data that is compatible with all
	   architectures.

       ~/.local/lib/arch-id
	   Location for placing public dynamic libraries. The architecture
	   identifier to use is defined on Multiarch Architecture Specifiers
	   (Tuples)[4] list.

       ~/.local/share
	   Resources shared between multiple packages, such as fonts or
	   artwork. Usually, the precise location and format of files stored
	   below this directory is subject to specifications that ensure
	   interoperability. If an application finds $XDG_DATA_HOME set, it
	   should use the directory specified in it instead of this directory.

UNPRIVILEGED WRITE ACCESS
       Unprivileged processes generally lack write access to most of the
       hierarchy.

       The exceptions for normal users are /tmp, /var/tmp, /dev/shm, as well
       as the home directory $HOME (usually found below /home) and the runtime
       directory $XDG_RUNTIME_DIR (found below /run/user) of the user, which
       are all writable.

       For unprivileged system processes, only /tmp, /var/tmp and /dev/shm are
       writable. If an unprivileged system process needs a private writable
       directory in /var or /run, it is recommended to either create it before
       dropping privileges in the daemon code, to create it via tmpfiles.d(5)
       fragments during boot, or via the RuntimeDirectory= directive of
       service units (see systemd.unit(5) for details).

NODE TYPES
       Unix file systems support different types of file nodes, including
       regular files, directories, symlinks, character and block device nodes,
       sockets and FIFOs.

       It is strongly recommended that /dev is the only location below which
       device nodes shall be placed. Similarly, /run shall be the only
       location to place sockets and FIFOs. Regular files, directories and
       symlinks may be used in all directories.

SYSTEM PACKAGES
       Developers of system packages should follow strict rules when placing
       their own files in the file system. The following table lists
       recommended locations for specific types of files supplied by the
       vendor.

       Table 1. System Package Vendor Files Locations
       ┌─────────────────────┬────────────────────────────┐
       │Directory	     │ Purpose			  │
       ├─────────────────────┼────────────────────────────┤
       │/usr/bin	     │ Package executables that	  │
       │		     │ shall appear in the $PATH  │
       │		     │ executable search path,	  │
       │		     │ compiled for any of the	  │
       │		     │ supported architectures	  │
       │		     │ compatible with the	  │
       │		     │ operating system. It is	  │
       │		     │ not recommended to place	  │
       │		     │ internal binaries or	  │
       │		     │ binaries that are not	  │
       │		     │ commonly invoked from the  │
       │		     │ shell in this directory,	  │
       │		     │ such as daemon binaries.	  │
       │		     │ As this directory is	  │
       │		     │ shared with most other	  │
       │		     │ packages of the system,	  │
       │		     │ special care should be	  │
       │		     │ taken to pick unique names │
       │		     │ for files placed here,	  │
       │		     │ that are unlikely to clash │
       │		     │ with other package's	  │
       │		     │ files.			  │
       ├─────────────────────┼────────────────────────────┤
       │/lib/arch-id	     │ Public shared libraries of │
       │		     │ the package. As above, be  │
       │		     │ careful with using too	  │
       │		     │ generic names, and pick	  │
       │		     │ unique names for your	  │
       │		     │ libraries to place here to │
       │		     │ avoid name clashes.	  │
       ├─────────────────────┼────────────────────────────┤
       │/lib/package	     │ Private static vendor	  │
       │		     │ resources of the package,  │
       │		     │ including private binaries │
       │		     │ and libraries, or any	  │
       │		     │ other kind of read-only	  │
       │		     │ vendor data.		  │
       ├─────────────────────┼────────────────────────────┤
       │/lib/arch-id/package │ Private other vendor	  │
       │		     │ resources of the package	  │
       │		     │ that are			  │
       │		     │ architecture-specific and  │
       │		     │ cannot be shared between	  │
       │		     │ architectures. Note that	  │
       │		     │ this generally does not	  │
       │		     │ include private		  │
       │		     │ executables since binaries │
       │		     │ of a specific architecture │
       │		     │ may be freely invoked from │
       │		     │ any other supported system │
       │		     │ architecture.		  │
       ├─────────────────────┼────────────────────────────┤
       │/usr/include/package │ Public C/C++ APIs of	  │
       │		     │ public shared libraries of │
       │		     │ the package.		  │
       └─────────────────────┴────────────────────────────┘

       Additional static vendor files may be installed in the /usr/share
       hierarchy to the locations defined by the various relevant
       specifications.

       During runtime, and for local configuration and state, additional
       directories are defined:

       Table 2. System Package Variable Files Locations
       ┌───────────────────┬────────────────────────────┐
       │Directory	   │ Purpose			│
       ├───────────────────┼────────────────────────────┤
       │/etc/package	   │ System-specific		│
       │		   │ configuration for the	│
       │		   │ package. It is recommended │
       │		   │ to default to safe		│
       │		   │ fallbacks if this		│
       │		   │ configuration is missing,	│
       │		   │ if this is possible.	│
       │		   │ Alternatively, a		│
       │		   │ tmpfiles.d(5) fragment may │
       │		   │ be used to copy or symlink │
       │		   │ the necessary files and	│
       │		   │ directories from		│
       │		   │ /usr/share/factory during	│
       │		   │ boot, via the "L" or "C"	│
       │		   │ directives.		│
       ├───────────────────┼────────────────────────────┤
       │/run/package	   │ Runtime data for the	│
       │		   │ package. Packages must be	│
       │		   │ able to create the		│
       │		   │ necessary subdirectories	│
       │		   │ in this tree on their own, │
       │		   │ since the directory is	│
       │		   │ flushed automatically on	│
       │		   │ boot. Alternatively, a	│
       │		   │ tmpfiles.d(5) fragment may │
       │		   │ be used to create the	│
       │		   │ necessary directories	│
       │		   │ during boot.		│
       │		   │ Alternatively, the		│
       │		   │ RuntimeDirectory=		│
       │		   │ directive of service units │
       │		   │ may be used (see		│
       │		   │ systemd.unit(5) for	│
       │		   │ details.)			│
       ├───────────────────┼────────────────────────────┤
       │/run/log/package   │ Runtime log data for the	│
       │		   │ package. As above, the	│
       │		   │ package needs to make sure │
       │		   │ to create this directory	│
       │		   │ if necessary, as it will	│
       │		   │ be flushed on every boot.	│
       ├───────────────────┼────────────────────────────┤
       │/var/cache/package │ Persistent cache data of	│
       │		   │ the package. If this	│
       │		   │ directory is flushed, the	│
       │		   │ application should work	│
       │		   │ correctly on next		│
       │		   │ invocation, though		│
       │		   │ possibly slowed down due	│
       │		   │ to the need to rebuild any │
       │		   │ local cache files. The	│
       │		   │ application must be	│
       │		   │ capable of recreating this │
       │		   │ directory should it be	│
       │		   │ missing and necessary.	│
       ├───────────────────┼────────────────────────────┤
       │/var/lib/package   │ Persistent private data of │
       │		   │ the package. This is the	│
       │		   │ primary place to put	│
       │		   │ persistent data that does	│
       │		   │ not fall into the other	│
       │		   │ categories listed.		│
       │		   │ Packages should be able to │
       │		   │ create the necessary	│
       │		   │ subdirectories in this	│
       │		   │ tree on their own, since	│
       │		   │ the directory might be	│
       │		   │ missing on boot.		│
       │		   │ Alternatively, a		│
       │		   │ tmpfiles.d(5) fragment may │
       │		   │ be used to create the	│
       │		   │ necessary directories	│
       │		   │ during boot.		│
       ├───────────────────┼────────────────────────────┤
       │/var/log/package   │ Persistent log data of the │
       │		   │ package. As above, the	│
       │		   │ package should make sure	│
       │		   │ to create this directory	│
       │		   │ if necessary, as it might	│
       │		   │ be missing.		│
       ├───────────────────┼────────────────────────────┤
       │/var/spool/package │ Persistent spool/queue	│
       │		   │ data of the package. As	│
       │		   │ above, the package should	│
       │		   │ make sure to create this	│
       │		   │ directory if necessary, as │
       │		   │ it might be missing.	│
       └───────────────────┴────────────────────────────┘

USER PACKAGES
       Programs running in user context should follow strict rules when
       placing their own files in the user's home directory. The following
       table lists recommended locations in the home directory for specific
       types of files supplied by the vendor if the application is installed
       in the home directory. (Note, however, that user applications installed
       system-wide should follow the rules outlined above regarding placing
       vendor files.)

       Table 3. User Package Vendor File Locations
       ┌─────────────────────────────┬────────────────────────────┐
       │Directory		     │ Purpose			  │
       ├─────────────────────────────┼────────────────────────────┤
       │~/.local/bin		     │ Package executables that	  │
       │			     │ shall appear in the $PATH  │
       │			     │ executable search path. It │
       │			     │ is not recommended to	  │
       │			     │ place internal executables │
       │			     │ or executables that are	  │
       │			     │ not commonly invoked from  │
       │			     │ the shell in this	  │
       │			     │ directory, such as daemon  │
       │			     │ executables. As this	  │
       │			     │ directory is shared with	  │
       │			     │ most other packages of the │
       │			     │ user, special care should  │
       │			     │ be taken to pick unique	  │
       │			     │ names for files placed	  │
       │			     │ here, that are unlikely to │
       │			     │ clash with other package's │
       │			     │ files.			  │
       ├─────────────────────────────┼────────────────────────────┤
       │~/.local/lib/arch-id	     │ Public shared libraries of │
       │			     │ the package. As above, be  │
       │			     │ careful with using too	  │
       │			     │ generic names, and pick	  │
       │			     │ unique names for your	  │
       │			     │ libraries to place here to │
       │			     │ avoid name clashes.	  │
       ├─────────────────────────────┼────────────────────────────┤
       │~/.local/lib/package	     │ Private, static vendor	  │
       │			     │ resources of the package,  │
       │			     │ compatible with any	  │
       │			     │ architecture, or any other │
       │			     │ kind of read-only vendor	  │
       │			     │ data.			  │
       ├─────────────────────────────┼────────────────────────────┤
       │~/.local/lib/arch-id/package │ Private other vendor	  │
       │			     │ resources of the package	  │
       │			     │ that are			  │
       │			     │ architecture-specific and  │
       │			     │ cannot be shared between	  │
       │			     │ architectures.		  │
       └─────────────────────────────┴────────────────────────────┘

       Additional static vendor files may be installed in the ~/.local/share
       hierarchy to the locations defined by the various relevant
       specifications.

       During runtime, and for local configuration and state, additional
       directories are defined:

       Table 4. User Package Variable File Locations
       ┌─────────────────────────┬────────────────────────────┐
       │Directory		 │ Purpose		      │
       ├─────────────────────────┼────────────────────────────┤
       │~/.config/package	 │ User-specific	      │
       │			 │ configuration and state    │
       │			 │ for the package. It is     │
       │			 │ required to default to     │
       │			 │ safe fallbacks if this     │
       │			 │ configuration is missing.  │
       ├─────────────────────────┼────────────────────────────┤
       │$XDG_RUNTIME_DIR/package │ User runtime data for the  │
       │			 │ package.		      │
       ├─────────────────────────┼────────────────────────────┤
       │~/.cache/package	 │ Persistent cache data of   │
       │			 │ the package. If this	      │
       │			 │ directory is flushed, the  │
       │			 │ application should work    │
       │			 │ correctly on next	      │
       │			 │ invocation, though	      │
       │			 │ possibly slowed down due   │
       │			 │ to the need to rebuild any │
       │			 │ local cache files. The     │
       │			 │ application must be	      │
       │			 │ capable of recreating this │
       │			 │ directory should it be     │
       │			 │ missing and necessary.     │
       └─────────────────────────┴────────────────────────────┘

SEE ALSO
       systemd(1), hier(7), systemd-path(1), systemd-gpt-auto-generator(8),
       sysctl.d(5), tmpfiles.d(5), pkg-config(1), systemd.unit(5)

NOTES
	1. File System Hierarchy
	   http://refspecs.linuxfoundation.org/FHS_2.3/fhs-2.3.html

	2. IEEE Std 1003.1
	   http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03

	3. XDG Base Directory Specification
	   http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html

	4. Multiarch Architecture Specifiers (Tuples)
	   https://wiki.debian.org/Multiarch/Tuples

	5. xdg-user-dirs
	   https://www.freedesktop.org/wiki/Software/xdg-user-dirs/

systemd 236						     FILE-HIERARCHY(7)
[top]

List of man pages available for Kali

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net