man/file-hierarchy.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   This file is part of systemd.
   7
   8   Copyright 2014 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
  14
  15   systemd is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 -->
  23
  24 <refentry id="file-hierarchy">
  25
  26         <refentryinfo>
  27                 <title>file-hierarchy</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>file-hierarchy</refentrytitle>
  42                 <manvolnum>7</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>file-hierarchy</refname>
  47                 <refpurpose>File system hierarchy overview</refpurpose>
  48         </refnamediv>
  49
  50         <refsect1>
  51                 <title>Description</title>
  52
  53                 <para>Operating systems using the
  54                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  55                 system and service manager are organized based on a
  56                 file system hierarchy inspired by UNIX, more
  57                 specificaly the hierarchy described in the <ulink
  58                 url="http://refspecs.linuxfoundation.org/FHS_2.3/fhs-2.3.html">File
  59                 System Hierarchy</ulink> specification and
  60                 <citerefentry><refentrytitle>hier</refentrytitle><manvolnum>7</manvolnum></citerefentry>. This
  61                 manual page describes a more minimal, modernized
  62                 subset of these specifications that defines more
  63                 strictly the suggestions and restrictions systemd
  64                 makes on the file system hierarchy.</para>
  65         </refsect1>
  66
  67         <refsect1>
  68                 <title>General Structure</title>
  69
  70                 <variablelist>
  71                         <varlistentry>
  72                                 <term><filename>/</filename></term>
  73                                 <listitem><para>The file system
  74                                 root. Usually writable, but this is
  75                                 not required. Possibly a temporary
  76                                 file system (<literal>tmpfs</literal>). Not shared with
  77                                 other hosts (unless read-only). The
  78                                 administrator may create additional
  79                                 top-level subdirectories in this tree,
  80                                 if required and the name does not
  81                                 conflict with any of the directories
  82                                 listed below.</para></listitem>
  83                         </varlistentry>
  84
  85                         <varlistentry>
  86                                 <term><filename>/boot</filename></term>
  87                                 <listitem><para>The boot partition
  88                                 used for bringing up the system. On
  89                                 EFI systems this is possibly the EFI
  90                                 System Partition, also see
  91                                 <citerefentry><refentrytitle>systemd-boot-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>. This
  92                                 directory is usually strictly local
  93                                 the host, and should be considered
  94                                 read-only, except when a new kernel or
  95                                 boot loader is installed. This
  96                                 directory only exists on systems that
  97                                 run on physical or emulated hardware
  98                                 that requires boot
  99                                 loaders.</para></listitem>
 100                         </varlistentry>
 101
 102                         <varlistentry>
 103                                 <term><filename>/etc</filename></term>
 104                                 <listitem><para>System-specific
 105                                 configuration. This directory may or
 106                                 may not be read-only. Frequently, this
 107                                 directory is pre-populated with
 108                                 vendor-supplied configuration files,
 109                                 but applications should not make
 110                                 assumptions about this directory
 111                                 being fully populated or populated at
 112                                 all, and should fall back to defaults
 113                                 if configuration is missing.</para></listitem>
 114                         </varlistentry>
 115
 116                         <varlistentry>
 117                                 <term><filename>/home</filename></term>
 118                                 <listitem><para>The location for
 119                                 normal user's home
 120                                 directories. Possibly shared with
 121                                 other systems, and never
 122                                 read-only. This directory should only
 123                                 be used for normal users, never for
 124                                 system users. This directory and
 125                                 possibly the directories contained
 126                                 within it might only become available
 127                                 or writable in late boot or even on
 128                                 user login only. This directory might
 129                                 be placed on limited-functionality
 130                                 network file systems, hence
 131                                 applications should not assume the
 132                                 full set of file API is available on
 133                                 this directory. Applications should
 134                                 generally not reference this directory
 135                                 directly, but via the per-user
 136                                 <varname>$HOME</varname> environment
 137                                 variable, or via the home directory
 138                                 field of the user
 139                                 database.</para></listitem>
 140                         </varlistentry>
 141
 142                         <varlistentry>
 143                                 <term><filename>/root</filename></term>
 144                                 <listitem><para>The home directory of
 145                                 the root user. The root user's home
 146                                 directory is located outside of
 147                                 <filename>/home</filename> in order to
 148                                 make sure the root user may log in
 149                                 even without <filename>/home</filename>
 150                                 being available and
 151                                 mounted.</para></listitem>
 152                         </varlistentry>
 153
 154                         <varlistentry>
 155                                 <term><filename>/srv</filename></term>
 156                                 <listitem><para>The place to store
 157                                 general server payload, managed by the
 158                                 administrator. No restrictions are
 159                                 made how this directory is organized
 160                                 internally. Generally writable, and
 161                                 possibly shared among systems. This
 162                                 directory might become available or
 163                                 writable only very late during
 164                                 boot.</para></listitem>
 165                         </varlistentry>
 166
 167                         <varlistentry>
 168                                 <term><filename>/tmp</filename></term>
 169                                 <listitem><para>The place for small
 170                                 temporary files. This directory is
 171                                 usually mounted as
 172                                 <literal>tmpfs</literal> instance, and
 173                                 should hence not be used for larger
 174                                 files. (Use
 175                                 <filename>/var/tmp</filename> for
 176                                 larger files.) Since the directory is
 177                                 accessible to other users of the
 178                                 system it is essential that this
 179                                 directory is only written to with the
 180                                 <citerefentry><refentrytitle>mkstemp</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 181                                 <citerefentry><refentrytitle>mkdtemp</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 182                                 and related calls. This directory is
 183                                 usually flushed at boot-up. Also,
 184                                 files that are not accessed within a
 185                                 certain time are usually automatically
 186                                 deleted. If applications find the
 187                                 environment variable
 188                                 <varname>$TMP</varname> set they
 189                                 should prefer using the directory
 190                                 specified in it over directly
 191                                 referencing
 192                                 <filename>/tmp</filename>.</para></listitem>
 193                         </varlistentry>
 194
 195                 </variablelist>
 196         </refsect1>
 197
 198         <refsect1>
 199                 <title>Runtime Data</title>
 200
 201                 <variablelist>
 202                         <varlistentry>
 203                                 <term><filename>/run</filename></term>
 204                                 <listitem><para>A
 205                                 <literal>tmpfs</literal> file system
 206                                 for system packages to place runtime
 207                                 data in. This directory is flushed on
 208                                 boot, and generally writable for
 209                                 priviliged programs
 210                                 only. Always writable.</para></listitem>
 211                         </varlistentry>
 212
 213                         <varlistentry>
 214                                 <term><filename>/run/log</filename></term>
 215                                 <listitem><para>Runtime system
 216                                 logs. System components may place
 217                                 private logs in this directory. Always
 218                                 writable, even when
 219                                 <filename>/var/log</filename> might
 220                                 not be accessible
 221                                 yet.</para></listitem>
 222                         </varlistentry>
 223
 224                         <varlistentry>
 225                                 <term><filename>/run/user</filename></term>
 226                                 <listitem><para>Contains per-user
 227                                 runtime directories, each usually
 228                                 invidually mounted
 229                                 <literal>tmpfs</literal>
 230                                 instances. Always writable, flushed at
 231                                 each reboot and when the user logs
 232                                 out. User code should not reference
 233                                 this directory directly, but via the
 234                                 <varname>$XDG_RUNTIME_DIR</varname>
 235                                 environment variable, as documented in
 236                                 the <ulink
 237                                 url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
 238                                 Base Directory
 239                                 Specification</ulink>.</para></listitem>
 240                         </varlistentry>
 241                 </variablelist>
 242         </refsect1>
 243
 244         <refsect1>
 245                 <title>Vendor-supplied Operating System Resources</title>
 246
 247                 <variablelist>
 248
 249                         <varlistentry>
 250                                 <term><filename>/usr</filename></term>
 251                                 <listitem><para>Vendor-supplied
 252                                 operating system resources. Usually
 253                                 read-only, but this is not
 254                                 required. Possibly shared between
 255                                 multiple hosts. This directory should
 256                                 not be modified by the administrator,
 257                                 except when installing or removing
 258                                 vendor-supplied
 259                                 packages.</para></listitem>
 260                         </varlistentry>
 261
 262                         <varlistentry>
 263                                 <term><filename>/usr/bin</filename></term>
 264                                 <listitem><para>Binaries for user
 265                                 commands, that shall appear in the
 266                                 <varname>$PATH</varname> search
 267                                 path. It is recommended not to place
 268                                 binaries in this directory that are
 269                                 not useful for invocation from a shell
 270                                 (such as daemon binaries); these
 271                                 should be placed in a subdirectory of
 272                                 <filename>/usr/lib</filename>
 273                                 instead.</para></listitem>
 274                         </varlistentry>
 275
 276                         <varlistentry>
 277                                 <term><filename>/usr/include</filename></term>
 278                                 <listitem><para>C and C++ API header
 279                                 files of system
 280                                 libraries.</para></listitem>
 281                         </varlistentry>
 282
 283                         <varlistentry>
 284                                 <term><filename>/usr/lib</filename></term>
 285                                 <listitem><para>System libraries and
 286                                 package-specific
 287                                 data.</para></listitem>
 288                         </varlistentry>
 289
 290                         <varlistentry>
 291                                 <term><filename>/usr/lib64</filename></term>
 292                                 <listitem><para>Secondary library
 293                                 directory for placing 64bit versions
 294                                 of system libraries in, if the primary
 295                                 architecture of the system is 32bit,
 296                                 and <filename>/usr/lib64</filename> is
 297                                 defined in the platform ABI. This
 298                                 directory should not be used for
 299                                 package-specific data, unless this
 300                                 data requires 64bit-specific versions,
 301                                 too.</para></listitem>
 302                         </varlistentry>
 303
 304                         <varlistentry>
 305                                 <term><filename>/usr/share</filename></term>
 306                                 <listitem><para>Resources shared
 307                                 betwen multiple packages, such as
 308                                 documentation, man pages, time zone
 309                                 information, fonts and other
 310                                 resources. Usually, the precise
 311                                 location and format of files stored
 312                                 below this directory is subject to
 313                                 specifications that ensure
 314                                 interoperability.</para></listitem>
 315                         </varlistentry>
 316
 317                         <varlistentry>
 318                                 <term><filename>/usr/share/doc</filename></term>
 319                                 <listitem><para>Documentation for the
 320                                 operating system or system
 321                                 packages.</para></listitem>
 322                         </varlistentry>
 323
 324                         <varlistentry>
 325                                 <term><filename>/usr/share/factory/etc</filename></term>
 326                                 <listitem><para>Repository for
 327                                 vendor-supplied default configuration
 328                                 files. This directory should be
 329                                 populated with pristine vendor versions
 330                                 of all configuration files that may be
 331                                 placed in
 332                                 <filename>/etc</filename>. This is
 333                                 useful to compare the local
 334                                 configuration of a system with vendor
 335                                 defaults and to populate the local
 336                                 configuration with
 337                                 defaults.</para></listitem>
 338                         </varlistentry>
 339
 340                         <varlistentry>
 341                                 <term><filename>/usr/share/factory/var</filename></term>
 342
 343                                 <listitem><para>Similar to
 344                                 <filename>/usr/share/factory/etc</filename>
 345                                 but for vendor versions of files in
 346                                 the variable, persistent data
 347                                 directory
 348                                 <filename>/var</filename>.</para></listitem>
 349
 350                         </varlistentry>
 351                 </variablelist>
 352         </refsect1>
 353
 354         <refsect1>
 355                 <title>Persistent Variable System Data</title>
 356
 357                 <variablelist>
 358                         <varlistentry>
 359                                 <term><filename>/var</filename></term>
 360                                 <listitem><para>Persistent, variable
 361                                 system data. Must be writable. This
 362                                 directory might be pre-populated with
 363                                 vendor-supplied data, but applications
 364                                 should be able to reconstruct
 365                                 necessary files and directories in
 366                                 this subhierarchy should they be
 367                                 missing, as the system might start up
 368                                 without this directory being
 369                                 populated. Persistency is recommended,
 370                                 but optional, to support ephemeral
 371                                 systems. This directory might become
 372                                 available or writable only very late
 373                                 during boot. Components that are
 374                                 required to operate during early boot
 375                                 hence shall not unconditionally rely
 376                                 on this directory.</para></listitem>
 377                         </varlistentry>
 378
 379                         <varlistentry>
 380                                 <term><filename>/var/cache</filename></term>
 381                                 <listitem><para>Persistent system
 382                                 cache data. System components may
 383                                 place non-essential data in this
 384                                 directory. Flushing this directory
 385                                 should have no effect on operation of
 386                                 programs, except for increased
 387                                 runtimes necessary to rebuild these
 388                                 caches.</para></listitem>
 389                         </varlistentry>
 390
 391                         <varlistentry>
 392                                 <term><filename>/var/lib</filename></term>
 393                                 <listitem><para>Persistent system
 394                                 data. System components may
 395                                 place private data in this
 396                                 directory.</para></listitem>
 397                         </varlistentry>
 398
 399                         <varlistentry>
 400                                 <term><filename>/var/log</filename></term>
 401                                 <listitem><para>Persistent system
 402                                 logs. System components may place
 403                                 private logs in this directory, though
 404                                 it is recommended to do most logging
 405                                 via the
 406                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 407                                 and
 408                                 <citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 409                                 calls.</para></listitem>
 410                         </varlistentry>
 411
 412                         <varlistentry>
 413                                 <term><filename>/var/spool</filename></term>
 414                                 <listitem><para>Persistent system
 415                                 spool data, such as printer or mail
 416                                 queues.</para></listitem>
 417                         </varlistentry>
 418
 419                         <varlistentry>
 420                                 <term><filename>/var/tmp</filename></term>
 421                                 <listitem><para>The place for larger
 422                                 and persistent temporary files. In
 423                                 contrast to <filename>/tmp</filename>
 424                                 this directory is usually mounted from
 425                                 a persistent physical file system and
 426                                 can thus accept larger files. (Use
 427                                 <filename>/tmp</filename> for smaller
 428                                 files.) This directory is generally
 429                                 not flushed at boot-up, but time-based
 430                                 cleanup of files that have not been
 431                                 accessed for a certain time is
 432                                 applied. The same security
 433                                 restrictions as with
 434                                 <filename>/tmp</filename> apply, and
 435                                 hence only
 436                                 <citerefentry><refentrytitle>mkstemp</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 437                                 <citerefentry><refentrytitle>mkdtemp</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 438                                 or similar calls should be used to
 439                                 make use of this directory. If
 440                                 applications find the environment
 441                                 variable <varname>$TMP</varname> set
 442                                 they should prefer using the directory
 443                                 specified in it over directly
 444                                 referencing
 445                                 <filename>/var/tmp</filename>.
 446                                 </para></listitem>
 447                         </varlistentry>
 448
 449                 </variablelist>
 450         </refsect1>
 451
 452         <refsect1>
 453                 <title>Virtual Kernel and API File Systems</title>
 454
 455                 <variablelist>
 456                         <varlistentry>
 457                                 <term><filename>/dev</filename></term>
 458                                 <listitem><para>The root directory for
 459                                 device nodes. Usually this directory
 460                                 is mounted as
 461                                 <literal>devtmpfs</literal> instance,
 462                                 but might be of a different type in
 463                                 sandboxed/containerized setups. This
 464                                 directory is managed jointly by the
 465                                 kernel and
 466                                 <citerefentry><refentrytitle>systemd-udevd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 467                                 and should not be written to by other
 468                                 components. A number of special
 469                                 purpose virtual file systems might be
 470                                 mounted below this
 471                                 directory.</para></listitem>
 472                         </varlistentry>
 473
 474                         <varlistentry>
 475                                 <term><filename>/dev/shm</filename></term>
 476                                 <listitem><para>Place for POSIX shared
 477                                 memory segments, as created via
 478                                 <citerefentry><refentrytitle>shm_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>. This
 479                                 directory is flushed on boot, and is a
 480                                 <literal>tmpfs</literal> file
 481                                 system. Since all users have write
 482                                 access to this directory, special care
 483                                 should be taken to avoid name clashes
 484                                 and vulnerabilities. For normal users,
 485                                 shared memory segments in this
 486                                 directory are usually deleted when the
 487                                 user logs out. Usually it is a better
 488                                 idea to use memory mapped files in
 489                                 <filename>/run</filename> (for system
 490                                 programs) or
 491                                 <varname>$XDG_RUNTIME_DIR</varname>
 492                                 (for user programs) instead of POSIX
 493                                 shared memory segments, since they
 494                                 directories are not world-writable and
 495                                 hence not vulnerable to
 496                                 security-sensitive name
 497                                 clashes.</para></listitem>
 498                         </varlistentry>
 499
 500                         <varlistentry>
 501                                 <term><filename>/proc</filename></term>
 502                                 <listitem><para>A virtual kernel file
 503                                 system exposing the process list and
 504                                 other functionality. This file system
 505                                 is mostly an API to interface with the
 506                                 kernel and not a place where normal
 507                                 files may be stored. For details, see
 508                                 <citerefentry><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>. A
 509                                 number of special purpose virtual file
 510                                 systems might be mounted below this
 511                                 directory.</para></listitem>
 512                         </varlistentry>
 513
 514                         <varlistentry>
 515                                 <term><filename>/proc/sys</filename></term>
 516                                 <listitem><para>A hierarchy below
 517                                 <filename>/proc</filename> that
 518                                 exposes a number of kernel
 519                                 tunables. The primary way to configure
 520                                 the settings in this API file tree is
 521                                 via
 522                                 <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 523                                 files. In sandboxed/containerized
 524                                 setups this directory is generally
 525                                 mounted read-only.</para></listitem>
 526                         </varlistentry>
 527
 528                         <varlistentry>
 529                                 <term><filename>/sys</filename></term>
 530                                 <listitem><para>A virtual kernel file
 531                                 system exposing discovered devices and
 532                                 other functionality. This file system
 533                                 is mostly an API to interface with the
 534                                 kernel and not a place where normal
 535                                 files may be stored. In
 536                                 sandboxed/containerized setups this
 537                                 directory is generally mounted
 538                                 read-only. A number of special purpose
 539                                 virtual file systems might be mounted
 540                                 below this
 541                                 directory.</para></listitem>
 542                         </varlistentry>
 543
 544
 545                 </variablelist>
 546         </refsect1>
 547
 548         <refsect1>
 549                 <title>Compatibility Symlinks</title>
 550
 551                 <variablelist>
 552                         <varlistentry>
 553                                 <term><filename>/bin</filename></term>
 554                                 <term><filename>/sbin</filename></term>
 555                                 <term><filename>/usr/sbin</filename></term>
 556
 557                                 <listitem><para>These compatibility
 558                                 symlinks point to
 559                                 <filename>/usr/bin</filename>,
 560                                 ensuring that scripts and binaries
 561                                 referencing these legacy paths
 562                                 correctly find their binaries.</para></listitem>
 563                         </varlistentry>
 564
 565                         <varlistentry>
 566                                 <term><filename>/lib</filename></term>
 567
 568                                 <listitem><para>This compatibility
 569                                 symlink points to
 570                                 <filename>/usr/lib</filename>,
 571                                 ensuring that binaries referencing
 572                                 this legacy path correctly find
 573                                 their libraries.</para></listitem>
 574                         </varlistentry>
 575
 576                         <varlistentry>
 577                                 <term><filename>/lib64</filename></term>
 578
 579                                 <listitem><para>This compatibility
 580                                 symlink points to
 581                                 <filename>/usr/lib64</filename>,
 582                                 ensuring that binaries referencing
 583                                 this legacy path correctly find their
 584                                 libraries. This symlink only exists on
 585                                 architectures whose ABI requires a
 586                                 64bit version of the library
 587                                 directory.</para></listitem>
 588                         </varlistentry>
 589
 590                         <varlistentry>
 591                                 <term><filename>/var/run</filename></term>
 592
 593                                 <listitem><para>This compatibility
 594                                 symlink points to
 595                                 <filename>/run</filename>, ensuring
 596                                 that programs referencing this legacy
 597                                 path correctly find their runtime
 598                                 data.</para></listitem>
 599                         </varlistentry>
 600
 601                 </variablelist>
 602         </refsect1>
 603
 604         <refsect1>
 605                 <title>System Packages</title>
 606
 607                 <para>Developers of system packages should follow
 608                 strict rules when placing their own files in the file
 609                 system. The following table lists recommended
 610                 locations for specific types of files.</para>
 611
 612                 <table>
 613                   <title>System Package Data Location</title>
 614                   <tgroup cols='2' align='left' colsep='1' rowsep='1'>
 615                     <colspec colname="directory" />
 616                     <colspec colname="purpose" />
 617                     <thead>
 618                       <row>
 619                         <entry>Directory</entry>
 620                         <entry>Purpose</entry>
 621                       </row>
 622                     </thead>
 623                     <tbody>
 624                       <row>
 625                         <entry><filename>/usr/bin</filename></entry>
 626                         <entry>Package executables that shall appear in the <varname>$PATH</varname> executable search path. 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 take to pick unique names for files placed here, that are unlikely to clash with other package's files.</entry>
 627                       </row>
 628                       <row>
 629                         <entry><filename>/usr/lib</filename></entry>
 630                         <entry>Public shared libraries of the package, compiled for the primary architecture of the operating system. As above, be careful with using too generic names, and pick unique names for your libraries to place here to avoid name clashes.</entry>
 631                       </row>
 632                       <row>
 633                         <entry><filename>/usr/lib/<replaceable>package</replaceable></filename></entry>
 634                         <entry>Private other vendor resources of the package, including private binaries and libraries, but also including any other kind of read-only vendor data.</entry>
 635                       </row>
 636                       <row>
 637                         <entry><filename>/usr/lib64</filename></entry>
 638                         <entry>Public shared libraries of the package, compiled for the secondary, 64bit architecture, if this is part of the platform ABI of the architecture.</entry>
 639                       </row>
 640                       <row>
 641                         <entry><filename>/usr/lib64/<replaceable>package</replaceable></filename></entry>
 642                         <entry>Private other vendor resources of the package that are architecture-specific and cannot be shared between primary and secondary architectures. Note that this generally does not include private binaries since binaries of the primary architecture may generally be invoked from secondary architecture code just fine.</entry>
 643                       </row>
 644                       <row>
 645                         <entry><filename>/usr/include/<replaceable>package</replaceable></filename></entry>
 646                         <entry>Public C/C++ APIs of public shared libraries of the package.</entry>
 647                       </row>
 648                       <row>
 649                         <entry><filename>/etc/<replaceable>package</replaceable></filename></entry>
 650                         <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 directores from <filename>/usr/share/factory</filename> during boot, via the <literal>L</literal> or <literal>C</literal> directives.</entry>
 651                       </row>
 652                       <row>
 653                         <entry><filename>/run/<replaceable>package</replaceable></filename></entry>
 654                         <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.</entry>
 655                       </row>
 656                       <row>
 657                         <entry><filename>/run/log/<replaceable>package</replaceable></filename></entry>
 658                         <entry>Runtime log data for the package.</entry>
 659                       </row>
 660                       <row>
 661                         <entry><filename>/var/cache/<replaceable>package</replaceable></filename></entry>
 662                         <entry>Persistent cache data of the package. If this directory is flushed the application should work correctly on next invocation, though possibly slowed done due to the need to rebuild any local cache files.</entry>
 663                       </row>
 664                       <row>
 665                         <entry><filename>/var/lib/<replaceable>package</replaceable></filename></entry>
 666                         <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>
 667                       </row>
 668                       <row>
 669                         <entry><filename>/var/log/<replaceable>package</replaceable></filename></entry>
 670                         <entry>Persistent log data of the package.</entry>
 671                       </row>
 672                       <row>
 673                         <entry><filename>/var/spool/<replaceable>package</replaceable></filename></entry>
 674                         <entry>Persistent spool/queue data of the package.</entry>
 675                       </row>
 676                     </tbody>
 677                   </tgroup>
 678                 </table>
 679         </refsect1>
 680
 681         <refsect1>
 682                 <title>See Also</title>
 683                 <para>
 684                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 685                         <citerefentry><refentrytitle>hier</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 686                         <citerefentry><refentrytitle>systemd-boot-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 687                         <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 688                 </para>
 689         </refsect1>
 690
 691 </refentry>