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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<refentry id="file-hierarchy">

<refentryinfo>

<title>file-hierarchy</title>

<productname>systemd</productname>

<authorgroup>

<author>

<contrib>Developer</contrib>

<firstname>Lennart</firstname>

<surname>Poettering</surname>

<email>lennart@poettering.net</email>

</author>

</authorgroup>

</refentryinfo>

<refmeta>

<refentrytitle>file-hierarchy</refentrytitle>

<manvolnum>7</manvolnum>

</refmeta>

<refnamediv>

<refname>file-hierarchy</refname>

<refpurpose>File system hierarchy overview</refpurpose>

</refnamediv>

<refsect1>

<title>Description</title>

<para>Operating systems using the

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>

system and service manager are organized based on a file system

hierarchy inspired by UNIX, more specifically the hierarchy

described in the <ulink

url="http://refspecs.linuxfoundation.org/FHS_2.3/fhs-2.3.html">File

System Hierarchy</ulink> specification and

<citerefentry project='man-pages'><refentrytitle>hier</refentrytitle><manvolnum>7</manvolnum></citerefentry>.

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.</para>

<para>Many of the paths described here are queriable

with the

<citerefentry><refentrytitle>systemd-path</refentrytitle><manvolnum>1</manvolnum></citerefentry>

tool.</para>

</refsect1>

<refsect1>

<title>General Structure</title>

<variablelist>

<varlistentry>

<term><filename>/</filename></term>

<listitem><para>The file system root. Usually writable, but

this is not required. Possibly a temporary file system

(<literal>tmpfs</literal>). Not shared with other hosts

(unless read-only). </para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/boot</filename></term>

<listitem><para>The boot partition used for bringing up the

system. On EFI systems, this is possibly the EFI System

Partition, also see

<citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.

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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/etc</filename></term>

<listitem><para>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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/home</filename></term>

<listitem><para>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 <varname>$HOME</varname>

environment variable, or via the home directory field of the

user database.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/root</filename></term>

<listitem><para>The home directory of the root user. The root

user's home directory is located outside of

<filename>/home</filename> in order to make sure the root user

may log in even without <filename>/home</filename> being

available and mounted.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/srv</filename></term>

<listitem><para>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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/tmp</filename></term>

<listitem><para>The place for small temporary files. This

directory is usually mounted as a <literal>tmpfs</literal>

instance, and should hence not be used for larger files. (Use

<filename>/var/tmp</filename> 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

<citerefentry project='man-pages'><refentrytitle>mkstemp</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry project='man-pages'><refentrytitle>mkdtemp</refentrytitle><manvolnum>3</manvolnum></citerefentry>

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 <varname>$TMPDIR</varname> set, they

should prefer using the directory specified in it over

directly referencing <filename>/tmp</filename> (see

<citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>

and

<ulink url="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03">IEEE

Std 1003.1</ulink> for details).</para></listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>Runtime Data</title>

<variablelist>

<varlistentry>

<term><filename>/run</filename></term>

<listitem><para>A <literal>tmpfs</literal> 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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/run/log</filename></term>

<listitem><para>Runtime system logs. System components may

place private logs in this directory. Always writable, even

when <filename>/var/log</filename> might not be accessible

yet.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/run/user</filename></term>

<listitem><para>Contains per-user runtime directories, each

usually individually mounted <literal>tmpfs</literal>

instances. Always writable, flushed at each reboot and when

the user logs out. User code should not reference this

directory directly, but via the

<varname>$XDG_RUNTIME_DIR</varname> environment variable, as

documented in the <ulink

url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG

Base Directory Specification</ulink>.</para></listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>Vendor-supplied Operating System Resources</title>

<variablelist>

<varlistentry>

<term><filename>/usr</filename></term>

<listitem><para>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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/usr/bin</filename></term>

<listitem><para>Binaries and executables for user commands

that shall appear in the <varname>$PATH</varname> 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

<filename>/usr/lib</filename> instead.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/usr/include</filename></term>

<listitem><para>C and C++ API header files of system

libraries.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/usr/lib</filename></term>

<listitem><para>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 <varname>$libdir</varname> (see below),

instead.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/usr/lib/<replaceable>arch-id</replaceable></filename></term>

<listitem><para>Location for placing dynamic libraries, also

called <varname>$libdir</varname>. The architecture identifier

to use is defined on <ulink

url="https://wiki.debian.org/Multiarch/Tuples">Multiarch

Architecture Specifiers (Tuples)</ulink> list. Legacy

locations of <varname>$libdir</varname> are

<filename>/usr/lib</filename>,

<filename>/usr/lib64</filename>. This directory should not be

used for package-specific data, unless this data is

architecture-dependent, too. To query

<varname>$libdir</varname> for the primary architecture of the

system, invoke:

<programlisting># systemd-path system-library-arch</programlisting></para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/usr/share</filename></term>

<listitem><para>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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/usr/share/doc</filename></term>

<listitem><para>Documentation for the operating system or

system packages.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/usr/share/factory/etc</filename></term>

<listitem><para>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 <filename>/etc</filename>. This is useful to

compare the local configuration of a system with vendor

defaults and to populate the local configuration with

defaults.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/usr/share/factory/var</filename></term>

<listitem><para>Similar to

<filename>/usr/share/factory/etc</filename>, but for vendor

versions of files in the variable, persistent data directory

<filename>/var</filename>.</para></listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>Persistent Variable System Data</title>

<variablelist>

<varlistentry>

<term><filename>/var</filename></term>

<listitem><para>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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/var/cache</filename></term>

<listitem><para>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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/var/lib</filename></term>

<listitem><para>Persistent system data. System components may

place private data in this directory.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/var/log</filename></term>

<listitem><para>Persistent system logs. System components may

place private logs in this directory, though it is recommended

to do most logging via the

<citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>

and

<citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry>

calls.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/var/spool</filename></term>

<listitem><para>Persistent system spool data, such as printer

or mail queues.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/var/tmp</filename></term>

<listitem><para>The place for larger and persistent temporary

files. In contrast to <filename>/tmp</filename>, this directory

is usually mounted from a persistent physical file system and

can thus accept larger files. (Use <filename>/tmp</filename>

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 <filename>/tmp</filename> apply, and

hence only

<citerefentry project='man-pages'><refentrytitle>mkstemp</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

<citerefentry project='man-pages'><refentrytitle>mkdtemp</refentrytitle><manvolnum>3</manvolnum></citerefentry>

or similar calls should be used to make use of this directory.

If applications find the environment variable

<varname>$TMPDIR</varname> set, they should prefer using the

directory specified in it over directly referencing

<filename>/var/tmp</filename> (see

<citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>

for details). </para></listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>Virtual Kernel and API File Systems</title>

<variablelist>

<varlistentry>

<term><filename>/dev</filename></term>

<listitem><para>The root directory for device nodes. Usually,

this directory is mounted as a <literal>devtmpfs</literal>

instance, but might be of a different type in

sandboxed/containerized setups. This directory is managed

jointly by the kernel and

<citerefentry><refentrytitle>systemd-udevd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

and should not be written to by other components. A number of

special purpose virtual file systems might be mounted below

this directory.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/dev/shm</filename></term>

<listitem><para>Place for POSIX shared memory segments, as

created via

<citerefentry project='die-net'><refentrytitle>shm_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>.

This directory is flushed on boot, and is a

<literal>tmpfs</literal> 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 <filename>/run</filename> (for system

programs) or <varname>$XDG_RUNTIME_DIR</varname> (for user

programs) instead of POSIX shared memory segments, since those

directories are not world-writable and hence not vulnerable to

security-sensitive name clashes.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/proc</filename></term>

<listitem><para>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

<citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>.

A number of special purpose virtual file systems might be

mounted below this directory.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/proc/sys</filename></term>

<listitem><para>A hierarchy below <filename>/proc</filename>

that exposes a number of kernel tunables. The primary way to

configure the settings in this API file tree is via

<citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>

files. In sandboxed/containerized setups, this directory is

generally mounted read-only.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/sys</filename></term>

<listitem><para>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.</para></listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>Compatibility Symlinks</title>

<variablelist>

<varlistentry>

<term><filename>/bin</filename></term>

<term><filename>/sbin</filename></term>

<term><filename>/usr/sbin</filename></term>

<listitem><para>These compatibility symlinks point to

<filename>/usr/bin</filename>, ensuring that scripts and

binaries referencing these legacy paths correctly find their

binaries.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/lib</filename></term>

<listitem><para>This compatibility symlink points to

<filename>/usr/lib</filename>, ensuring that programs

referencing this legacy path correctly find their

resources.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/lib64</filename></term>

<listitem><para>On some architecture ABIs, this compatibility

symlink points to <varname>$libdir</varname>, 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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>/var/run</filename></term>

<listitem><para>This compatibility symlink points to

<filename>/run</filename>, ensuring that programs referencing

this legacy path correctly find their runtime

data.</para></listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>Home Directory</title>

<para>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 <ulink

url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG

Base Directory Specification</ulink>. Additional locations for

high-level user resources are defined by <ulink

url="http://www.freedesktop.org/wiki/Software/xdg-user-dirs/">xdg-user-dirs</ulink>.</para>

<variablelist>

<varlistentry>

<term><filename>~/.cache</filename></term>

<listitem><para>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

<varname>$XDG_CACHE_HOME</varname> set, is should use the

directory specified in it instead of this

directory.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>~/.config</filename></term>

<listitem><para>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 <varname>$XDG_CONFIG_HOME</varname> set, is

should use the directory specified in it instead of this

directory.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>~/.local/bin</filename></term>

<listitem><para>Executables that shall appear in the user's

<varname>$PATH</varname> 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 <filename>~/.local/lib</filename> 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.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>~/.local/lib</filename></term>

<listitem><para>Static, private vendor data that is compatible

with all architectures.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>~/.local/lib/<replaceable>arch-id</replaceable></filename></term>

<listitem><para>Location for placing public dynamic libraries.

The architecture identifier to use is defined on <ulink

url="https://wiki.debian.org/Multiarch/Tuples">Multiarch

Architecture Specifiers (Tuples)</ulink>

list.</para></listitem>

</varlistentry>

<varlistentry>

<term><filename>~/.local/share</filename></term>

<listitem><para>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 <varname>$XDG_DATA_HOME</varname> set, is should use the

directory specified in it instead of this

directory.</para></listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>Unprivileged Write Access</title>

<para>Unprivileged processes generally lack write access to most

of the hierarchy.</para>

<para>The exceptions for normal users are

<filename>/tmp</filename>,

<filename>/var/tmp</filename>,

<filename>/dev/shm</filename>, as well as the home directory

<varname>$HOME</varname> (usually found below

<filename>/home</filename>) and the runtime directory

<varname>$XDG_RUNTIME_DIR</varname> (found below

<filename>/run/user</filename>) of the user, which are all

writable.</para>

<para>For unprivileged system processes, only

<filename>/tmp</filename>,

<filename>/var/tmp</filename> and

<filename>/dev/shm</filename> are writable. If an

unprivileged system process needs a private writable directory in

<filename>/var</filename> or <filename>/run</filename>, it is

recommended to either create it before dropping privileges in the

daemon code, to create it via

<citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>

fragments during boot, or via the

<varname>RuntimeDirectory=</varname> directive of service units

(see

<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>

for details).</para>

</refsect1>

<refsect1>

<title>Node Types</title>

<para>Unix file systems support different types of file nodes,

including regular files, directories, symlinks, character and

block device nodes, sockets and FIFOs.</para>

<para>It is strongly recommended that <filename>/dev</filename> is

the only location below which device nodes shall be placed.

Similar, <filename>/run</filename> shall be the only location to

place sockets and FIFOs. Regular files, directories and symlinks

may be used in all directories.</para>

</refsect1>

<refsect1>

<title>System Packages</title>

<para>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.</para>

<table>

<title>System Package Vendor Files Locations</title>

<tgroup cols='2' align='left' colsep='1' rowsep='1'>

<colspec colname="directory" />

<colspec colname="purpose" />

<thead>

<row>

<entry>Directory</entry>

<entry>Purpose</entry>

</row>

</thead>

<tbody>

<row>

<entry><filename>/usr/bin</filename></entry>

<entry>Package executables that shall appear in the <varname>$PATH</varname> 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.</entry>

</row>

<row>

<entry><filename>/usr/lib/<replaceable>arch-id</replaceable></filename></entry>

<entry>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.</entry>

</row>

<row>

<entry><filename>/usr/lib/<replaceable>package</replaceable></filename></entry>

<entry>Private static vendor resources of the package, including private binaries and libraries, or any other kind of read-only vendor data.</entry>

</row>

<row>

<entry><filename>/usr/lib/<replaceable>arch-id</replaceable>/<replaceable>package</replaceable></filename></entry>

<entry>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.</entry>

</row>

<row>

<entry><filename>/usr/include/<replaceable>package</replaceable></filename></entry>

<entry>Public C/C++ APIs of public shared libraries of the package.</entry>

</row>

</tbody>

</tgroup>

</table>

<para>Additional static vendor files may be installed in the

<filename>/usr/share</filename> hierarchy to the locations

defined by the various relevant specifications.</para>

<para>During runtime, and for local configuration and state,

additional directories are defined:</para>

<table>

<title>System Package Variable Files Locations</title>

<tgroup cols='2' align='left' colsep='1' rowsep='1'>

<colspec colname="directory" />

<colspec colname="purpose" />

<thead>

<row>

<entry>Directory</entry>

<entry>Purpose</entry>

</row>

</thead>

<tbody>

<row>

<entry><filename>/etc/<replaceable>package</replaceable></filename></entry>

<entry>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 <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> fragment may be used to copy or symlink the necessary files and directories from <filename>/usr/share/factory</filename> during boot, via the <literal>L</literal> or <literal>C</literal> directives.</entry>

</row>

<row>

<entry><filename>/run/<replaceable>package</replaceable></filename></entry>

<entry>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 <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> fragment may be used to create the necessary directories during boot. Alternatively, the <varname>RuntimeDirectory=</varname> directive of service units may be used (see <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.)</entry>

</row>

<row>

<entry><filename>/run/log/<replaceable>package</replaceable></filename></entry>

<entry>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.</entry>

</row>

<row>

<entry><filename>/var/cache/<replaceable>package</replaceable></filename></entry>

<entry>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.</entry>

</row>

<row>

<entry><filename>/var/lib/<replaceable>package</replaceable></filename></entry>

<entry>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 <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> fragment may be used to create the necessary directories during boot.</entry>

</row>

<row>

<entry><filename>/var/log/<replaceable>package</replaceable></filename></entry>

<entry>Persistent log data of the package. As above, the package should make sure to create this directory if necessary, as it might be missing.</entry>

</row>

<row>

<entry><filename>/var/spool/<replaceable>package</replaceable></filename></entry>

<entry>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.</entry>

</row>

</tbody>

</tgroup>

</table>

</refsect1>

<refsect1>

<title>User Packages</title>

<para>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.)</para>

<table>

<title>User Package Vendor File Locations</title>

<tgroup cols='2' align='left' colsep='1' rowsep='1'>

<colspec colname="directory" />

<colspec colname="purpose" />

<thead>

<row>

<entry>Directory</entry>

<entry>Purpose</entry>

</row>

</thead>

<tbody>

<row>

<entry><filename>~/.local/bin</filename></entry>

<entry>Package executables that shall appear in the <varname>$PATH</varname> 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.</entry>

</row>

<row>

<entry><filename>~/.local/lib/<replaceable>arch-id</replaceable></filename></entry>

<entry>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.</entry>

</row>

<row>

<entry><filename>~/.local/lib/<replaceable>package</replaceable></filename></entry>

<entry>Private, static vendor resources of the package, compatible with any architecture, or any other kind of read-only vendor data.</entry>

</row>

<row>

<entry><filename>~/.local/lib/<replaceable>arch-id</replaceable>/<replaceable>package</replaceable></filename></entry>

<entry>Private other vendor resources of the package that are architecture-specific and cannot be shared between architectures.</entry>

</row>

</tbody>

</tgroup>

</table>

<para>Additional static vendor files may be installed in the

<filename>~/.local/share</filename> hierarchy to the locations

defined by the various relevant specifications.</para>

<para>During runtime, and for local configuration and state,

additional directories are defined:</para>

<table>

<title>User Package Variable File Locations</title>

<tgroup cols='2' align='left' colsep='1' rowsep='1'>

<colspec colname="directory" />

<colspec colname="purpose" />

<thead>

<row>

<entry>Directory</entry>

<entry>Purpose</entry>

</row>

</thead>

<tbody>

<row>

<entry><filename>~/.config/<replaceable>package</replaceable></filename></entry>

<entry>User-specific configuration and state for the package. It is required to default to safe fallbacks if this configuration is missing.</entry>

</row>

<row>

<entry><filename><varname>$XDG_RUNTIME_DIR</varname>/<replaceable>package</replaceable></filename></entry>

<entry>User runtime data for the package.</entry>

</row>

<row>

<entry><filename>~/.cache/<replaceable>package</replaceable></filename></entry>

<entry>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.</entry>

</row>

</tbody>

</tgroup>

</table>

</refsect1>

<refsect1>

<title>See Also</title>

<para>

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry project='man-pages'><refentrytitle>hier</refentrytitle><manvolnum>7</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-path</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>

</para>

</refsect1>

</refentry>