man/tmpfiles.d.xml

   1 <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   3 <!--
   4   SPDX-License-Identifier: LGPL-2.1+
   5
   6   This file is part of systemd.
   7
   8   Copyright 2010 Brandon Philips
   9 -->
  10 <refentry id="tmpfiles.d">
  11
  12   <refentryinfo>
  13     <title>tmpfiles.d</title>
  14     <productname>systemd</productname>
  15
  16     <authorgroup>
  17       <author>
  18         <contrib>Documentation</contrib>
  19         <firstname>Brandon</firstname>
  20         <surname>Philips</surname>
  21         <email>brandon@ifup.org</email>
  22       </author>
  23     </authorgroup>
  24   </refentryinfo>
  25
  26   <refmeta>
  27     <refentrytitle>tmpfiles.d</refentrytitle>
  28     <manvolnum>5</manvolnum>
  29   </refmeta>
  30
  31   <refnamediv>
  32     <refname>tmpfiles.d</refname>
  33     <refpurpose>Configuration for creation, deletion and cleaning of
  34     volatile and temporary files</refpurpose>
  35   </refnamediv>
  36
  37   <refsynopsisdiv>
  38     <para><literallayout><filename>/etc/tmpfiles.d/*.conf</filename>
  39 <filename>/run/tmpfiles.d/*.conf</filename>
  40 <filename>/usr/lib/tmpfiles.d/*.conf</filename>
  41     </literallayout></para>
  42
  43     <para><literallayout><filename>~/.config/user-tmpfiles.d/*.conf</filename>
  44 <filename>$XDG_RUNTIME_DIR/user-tmpfiles.d/*.conf</filename>
  45 <filename>~/.local/share/user-tmpfiles.d/*.conf</filename>
  46 <filename>…</filename>
  47 <filename>/usr/share/user-tmpfiles.d/*.conf</filename>
  48     </literallayout></para>
  49   </refsynopsisdiv>
  50
  51   <refsect1>
  52     <title>Description</title>
  53
  54     <para><command>systemd-tmpfiles</command> uses the configuration
  55     files from the above directories to describe the creation,
  56     cleaning and removal of volatile and temporary files and
  57     directories which usually reside in directories such as
  58     <filename>/run</filename> or <filename>/tmp</filename>.</para>
  59
  60     <para>Volatile and temporary files and directories are those
  61     located in <filename>/run</filename> (and its alias
  62     <filename>/var/run</filename>), <filename>/tmp</filename>,
  63     <filename>/var/tmp</filename>, the API file systems such as
  64     <filename>/sys</filename> or <filename>/proc</filename>, as well
  65     as some other directories below <filename>/var</filename>.</para>
  66
  67     <para>System daemons frequently require private runtime
  68     directories below <filename>/run</filename> to place communication
  69     sockets and similar in. For these, consider declaring them in
  70     their unit files using <varname>RuntimeDirectory=</varname> (see
  71     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  72     for details), if this is feasible.</para>
  73   </refsect1>
  74
  75   <refsect1>
  76     <title>Configuration Directories and Precedence</title>
  77
  78     <para>Each configuration file shall be named in the style of
  79     <filename><replaceable>package</replaceable>.conf</filename> or
  80     <filename><replaceable>package</replaceable>-<replaceable>part</replaceable>.conf</filename>.
  81     The second variant should be used when it is desirable to make it
  82     easy to override just this part of configuration.</para>
  83
  84     <para>Files in <filename>/etc/tmpfiles.d</filename> override files
  85     with the same name in <filename>/usr/lib/tmpfiles.d</filename> and
  86     <filename>/run/tmpfiles.d</filename>. Files in
  87     <filename>/run/tmpfiles.d</filename> override files with the same
  88     name in <filename>/usr/lib/tmpfiles.d</filename>. Packages should
  89     install their configuration files in
  90     <filename>/usr/lib/tmpfiles.d</filename>. Files in
  91     <filename>/etc/tmpfiles.d</filename> are reserved for the local
  92     administrator, who may use this logic to override the
  93     configuration files installed by vendor packages. All
  94     configuration files are sorted by their filename in lexicographic
  95     order, regardless of which of the directories they reside in. If
  96     multiple files specify the same path, the entry in the file with
  97     the lexicographically earliest name will be applied.  All other
  98     conflicting entries will be logged as errors. When two lines are
  99     prefix and suffix of each other, then the prefix is always
 100     processed first, the suffix later. Lines that take globs are
 101     applied after those accepting no globs. If multiple operations
 102     shall be applied on the same file, (such as ACL, xattr, file
 103     attribute adjustments), these are always done in the same fixed
 104     order. Otherwise, the files/directories are processed in the order
 105     they are listed.</para>
 106
 107     <para>If the administrator wants to disable a configuration file
 108     supplied by the vendor, the recommended way is to place a symlink
 109     to <filename>/dev/null</filename> in
 110     <filename>/etc/tmpfiles.d/</filename> bearing the same filename.
 111     </para>
 112   </refsect1>
 113
 114   <refsect1>
 115     <title>Configuration File Format</title>
 116
 117     <para>The configuration format is one line per path containing
 118     type, path, mode, ownership, age, and argument fields:</para>
 119
 120     <programlisting>#Type Path        Mode UID  GID  Age Argument
 121 d     /run/user   0755 root root 10d -
 122 L     /tmp/foobar -    -    -    -   /dev/null</programlisting>
 123
 124     <para>Fields may be enclosed within quotes and contain C-style escapes.</para>
 125
 126     <refsect2>
 127       <title>Type</title>
 128
 129       <para>The type consists of a single letter and optionally an
 130       exclamation mark.</para>
 131
 132       <para>The following line types are understood:</para>
 133
 134       <variablelist>
 135         <varlistentry>
 136           <term><varname>f</varname></term>
 137           <listitem><para>Create a file if it does not exist yet. If the argument parameter is given and the file did
 138           not exist yet, it will be written to the file. Does not follow symlinks.</para></listitem>
 139         </varlistentry>
 140
 141         <varlistentry>
 142           <term><varname>F</varname></term>
 143           <listitem><para>Create or truncate a file. If the argument
 144           parameter is given, it will be written to the file. Does not follow symlinks.</para>
 145           </listitem>
 146         </varlistentry>
 147
 148         <varlistentry>
 149           <term><varname>w</varname></term>
 150           <listitem><para>Write the argument parameter to a file, if
 151           the file exists.  Lines of this type accept shell-style
 152           globs in place of normal path names. The argument parameter
 153           will be written without a trailing newline. C-style
 154           backslash escapes are interpreted. Follows
 155           symlinks.</para></listitem>
 156         </varlistentry>
 157
 158         <varlistentry>
 159           <term><varname>d</varname></term>
 160           <listitem><para>Create a directory. The mode and ownership will be adjusted if
 161           specified and the directory already exists. Contents of this directory are subject
 162           to time based cleanup if the age argument is specified.</para></listitem>
 163         </varlistentry>
 164
 165         <varlistentry>
 166           <term><varname>D</varname></term>
 167           <listitem><para>Similar to <varname>d</varname>, but in addition the contents
 168           of the directory will be removed when <option>--remove</option> is used.
 169           </para></listitem>
 170         </varlistentry>
 171
 172         <varlistentry>
 173           <term><varname>e</varname></term>
 174           <listitem><para>Similar to <varname>d</varname>, but the directory will not be created if
 175           it does not exist. Lines of this type accept shell-style globs in place of normal path
 176           names. For this entry to be useful, at least one of the mode, uid, gid, or age arguments
 177           must be specified, since otherwise this entry has no effect. If the age argument is
 178           <literal>0</literal>, contents of the directory will be unconditionally deleted every time
 179           <command>systemd-tmpfiles --clean</command> is run. This can be useful when combined with
 180           <varname>!</varname>, see the examples.</para></listitem>
 181         </varlistentry>
 182
 183         <varlistentry>
 184           <term><varname>v</varname></term>
 185           <listitem><para>Create a subvolume if the path does not
 186           exist yet, the file system supports subvolumes (btrfs), and
 187           the system itself is installed into a subvolume
 188           (specifically: the root directory <filename>/</filename> is
 189           itself a subvolume). Otherwise, create a normal directory, in
 190           the same way as <varname>d</varname>. A subvolume created
 191           with this line type is not assigned to any higher-level
 192           quota group. For that, use <varname>q</varname> or
 193           <varname>Q</varname>, which allow creating simple quota
 194           group hierarchies, see below.</para></listitem>
 195         </varlistentry>
 196
 197         <varlistentry>
 198           <term><varname>q</varname></term>
 199           <listitem><para>Similar to <varname>v</varname>. However,
 200           makes sure that the subvolume will be assigned to the same
 201           higher-level quota groups as the subvolume it has been
 202           created in. This ensures that higher-level limits and
 203           accounting applied to the parent subvolume also include the
 204           specified subvolume. On non-btrfs file systems, this line
 205           type is identical to <varname>d</varname>. If the subvolume
 206           already exists and is already assigned to one or more higher
 207           level quota groups, no change to the quota hierarchy is
 208           made. Also see <varname>Q</varname> below. See <citerefentry
 209           project='die-net'><refentrytitle>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 210           for details about the btrfs quota group
 211           concept.</para></listitem>
 212         </varlistentry>
 213
 214         <varlistentry>
 215           <term><varname>Q</varname></term>
 216           <listitem><para>Similar to <varname>q</varname>. However,
 217           instead of copying the higher-level quota group assignments
 218           from the parent as-is, the lowest quota group of the parent
 219           subvolume is determined that is not the leaf quota
 220           group. Then, an "intermediary" quota group is inserted that
 221           is one level below this level, and shares the same ID part
 222           as the specified subvolume. If no higher-level quota group
 223           exists for the parent subvolume, a new quota group at level
 224           255 sharing the same ID as the specified subvolume is
 225           inserted instead. This new intermediary quota group is then
 226           assigned to the parent subvolume's higher-level quota
 227           groups, and the specified subvolume's leaf quota group is
 228           assigned to it.</para>
 229
 230           <para>Effectively, this has a similar effect as
 231           <varname>q</varname>, however introduces a new higher-level
 232           quota group for the specified subvolume that may be used to
 233           enforce limits and accounting to the specified subvolume and
 234           children subvolume created within it. Thus, by creating
 235           subvolumes only via <varname>q</varname> and
 236           <varname>Q</varname>, a concept of "subtree quotas" is
 237           implemented. Each subvolume for which <varname>Q</varname>
 238           is set will get a "subtree" quota group created, and all
 239           child subvolumes created within it will be assigned to
 240           it. Each subvolume for which <varname>q</varname> is set
 241           will not get such a "subtree" quota group, but it is ensured
 242           that they are added to the same "subtree" quota group as their
 243           immediate parents.</para>
 244
 245           <para>It is recommended to use
 246           <varname>Q</varname> for subvolumes that typically contain
 247           further subvolumes, and where it is desirable to have
 248           accounting and quota limits on all child subvolumes
 249           together. Examples for <varname>Q</varname> are typically
 250           <filename>/home</filename> or
 251           <filename>/var/lib/machines</filename>. In contrast,
 252           <varname>q</varname> should be used for subvolumes that
 253           either usually do not include further subvolumes or where no
 254           accounting and quota limits are needed that apply to all
 255           child subvolumes together. Examples for <varname>q</varname>
 256           are typically <filename>/var</filename> or
 257           <filename>/var/tmp</filename>. As with <varname>Q</varname>,
 258           <varname>q</varname> has no effect on the quota group
 259           hierarchy if the subvolume exists and already has at least
 260           one higher-level quota group assigned.</para></listitem>
 261         </varlistentry>
 262
 263         <varlistentry>
 264           <term><varname>p</varname></term>
 265           <term><varname>p+</varname></term>
 266           <listitem><para>Create a named pipe (FIFO) if it does not
 267           exist yet. If suffixed with <varname>+</varname> and a file
 268           already exists where the pipe is to be created, it will be
 269           removed and be replaced by the pipe.</para></listitem>
 270         </varlistentry>
 271
 272         <varlistentry>
 273           <term><varname>L</varname></term>
 274           <term><varname>L+</varname></term>
 275           <listitem><para>Create a symlink if it does not exist
 276           yet. If suffixed with <varname>+</varname> and a file or
 277           directory already exists where the symlink is to be created,
 278           it will be removed and be replaced by the symlink. If the
 279           argument is omitted, symlinks to files with the same name
 280           residing in the directory
 281           <filename>/usr/share/factory/</filename> are created. Note
 282           that permissions and ownership on symlinks are ignored.
 283           </para></listitem>
 284         </varlistentry>
 285
 286         <varlistentry>
 287           <term><varname>c</varname></term>
 288           <term><varname>c+</varname></term>
 289           <listitem><para>Create a character device node if it does
 290           not exist yet. If suffixed with <varname>+</varname> and a
 291           file already exists where the device node is to be created,
 292           it will be removed and be replaced by the device node. It is
 293           recommended to suffix this entry with an exclamation mark to
 294           only create static device nodes at boot, as udev will not
 295           manage static device nodes that are created at runtime.
 296           </para></listitem>
 297         </varlistentry>
 298
 299         <varlistentry>
 300           <term><varname>b</varname></term>
 301           <term><varname>b+</varname></term>
 302           <listitem><para>Create a block device node if it does not
 303           exist yet. If suffixed with <varname>+</varname> and a file
 304           already exists where the device node is to be created, it
 305           will be removed and be replaced by the device node. It is
 306           recommended to suffix this entry with an exclamation mark to
 307           only create static device nodes at boot, as udev will not
 308           manage static device nodes that are created at runtime.
 309           </para></listitem>
 310         </varlistentry>
 311
 312         <varlistentry>
 313           <term><varname>C</varname></term>
 314           <listitem><para>Recursively copy a file or directory, if the
 315           destination files or directories do not exist yet. Note that
 316           this command will not descend into subdirectories if the
 317           destination directory already exists. Instead, the entire
 318           copy operation is skipped. If the argument is omitted, files
 319           from the source directory
 320           <filename>/usr/share/factory/</filename> with the same name
 321           are copied. Does not follow symlinks.</para></listitem>
 322         </varlistentry>
 323
 324         <varlistentry>
 325           <term><varname>x</varname></term>
 326           <listitem><para>Ignore a path during cleaning. Use this type
 327           to exclude paths from clean-up as controlled with the Age
 328           parameter. Note that lines of this type do not influence the
 329           effect of <varname>r</varname> or <varname>R</varname>
 330           lines. Lines of this type accept shell-style globs in place
 331           of normal path names.  </para></listitem>
 332         </varlistentry>
 333
 334         <varlistentry>
 335           <term><varname>X</varname></term>
 336           <listitem><para>Ignore a path during cleaning. Use this type
 337           to exclude paths from clean-up as controlled with the Age
 338           parameter. Unlike <varname>x</varname>, this parameter will
 339           not exclude the content if path is a directory, but only
 340           directory itself. Note that lines of this type do not
 341           influence the effect of <varname>r</varname> or
 342           <varname>R</varname> lines. Lines of this type accept
 343           shell-style globs in place of normal path names.
 344           </para></listitem>
 345         </varlistentry>
 346
 347         <varlistentry>
 348           <term><varname>r</varname></term>
 349           <listitem><para>Remove a file or directory if it exists.
 350           This may not be used to remove non-empty directories, use
 351           <varname>R</varname> for that.  Lines of this type accept
 352           shell-style globs in place of normal path
 353           names. Does not follow symlinks.</para></listitem>
 354         </varlistentry>
 355
 356         <varlistentry>
 357           <term><varname>R</varname></term>
 358           <listitem><para>Recursively remove a path and all its
 359           subdirectories (if it is a directory). Lines of this type
 360           accept shell-style globs in place of normal path
 361           names. Does not follow symlinks.</para></listitem>
 362         </varlistentry>
 363
 364         <varlistentry>
 365           <term><varname>z</varname></term>
 366           <listitem><para>Adjust the access mode, group and user, and
 367           restore the SELinux security context of a file or directory,
 368           if it exists. Lines of this type accept shell-style globs in
 369           place of normal path names. Does not follow symlinks.</para></listitem>
 370         </varlistentry>
 371
 372         <varlistentry>
 373           <term><varname>Z</varname></term>
 374           <listitem><para>Recursively set the access mode, group and
 375           user, and restore the SELinux security context of a file or
 376           directory if it exists, as well as of its subdirectories and
 377           the files contained therein (if applicable). Lines of this
 378           type accept shell-style globs in place of normal path
 379           names. Does not follow symlinks.  </para></listitem>
 380         </varlistentry>
 381
 382         <varlistentry>
 383           <term><varname>t</varname></term>
 384           <listitem><para>Set extended attributes. Lines of this type
 385           accept shell-style globs in place of normal path names.
 386           This can be useful for setting SMACK labels. Does not follow
 387           symlinks.</para></listitem>
 388         </varlistentry>
 389
 390         <varlistentry>
 391           <term><varname>T</varname></term>
 392           <listitem><para>Recursively set extended attributes. Lines
 393           of this type accept shell-style globs in place of normal
 394           path names.  This can be useful for setting SMACK
 395           labels. Does not follow symlinks.  </para></listitem>
 396         </varlistentry>
 397
 398         <varlistentry>
 399           <term><varname>h</varname></term>
 400           <listitem><para>Set file/directory attributes. Lines of this type
 401           accept shell-style globs in place of normal path names.</para>
 402
 403           <para>The format of the argument field is
 404           <varname>[+-=][aAcCdDeijsStTu] </varname>. The prefix
 405           <varname>+</varname> (the default one) causes the
 406           attribute(s) to be added; <varname>-</varname> causes the
 407           attribute(s) to be removed; <varname>=</varname> causes the
 408           attributes to be set exactly as the following letters. The
 409           letters <literal>aAcCdDeijsStTu</literal> select the new
 410           attributes for the files, see
 411           <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle>
 412           <manvolnum>1</manvolnum></citerefentry> for further information.
 413           </para>
 414           <para>Passing only <varname>=</varname> as argument resets
 415           all the file attributes listed above. It has to be pointed
 416           out that the <varname>=</varname> prefix limits itself to
 417           the attributes corresponding to the letters listed here. All
 418           other attributes will be left untouched. Does not follow
 419           symlinks.</para>
 420           </listitem>
 421         </varlistentry>
 422
 423         <varlistentry>
 424           <term><varname>H</varname></term>
 425           <listitem><para>Recursively set file/directory attributes. Lines
 426           of this type accept shell-style globs in place of normal
 427           path names. Does not follow symlinks.
 428           </para></listitem>
 429         </varlistentry>
 430
 431         <varlistentry>
 432           <term><varname>a</varname></term>
 433           <term><varname>a+</varname></term>
 434           <listitem><para>Set POSIX ACLs (access control lists). If
 435           suffixed with <varname>+</varname>, the specified entries will
 436           be added to the existing set.
 437           <command>systemd-tmpfiles</command> will automatically add
 438           the required base entries for user and group based on the
 439           access mode of the file, unless base entries already exist
 440           or are explicitly specified. The mask will be added if not
 441           specified explicitly or already present. Lines of this type
 442           accept shell-style globs in place of normal path names. This
 443           can be useful for allowing additional access to certain
 444           files. Does not follow symlinks.</para></listitem>
 445         </varlistentry>
 446
 447         <varlistentry>
 448           <term><varname>A</varname></term>
 449           <term><varname>A+</varname></term>
 450           <listitem><para>Same as <varname>a</varname> and
 451           <varname>a+</varname>, but recursive. Does not follow
 452           symlinks.</para></listitem>
 453         </varlistentry>
 454       </variablelist>
 455
 456       <para>If the exclamation mark is used, this line is only safe of
 457       execute during boot, and can break a running system. Lines
 458       without the exclamation mark are presumed to be safe to execute
 459       at any time, e.g. on package upgrades.
 460       <command>systemd-tmpfiles</command> will execute line with an
 461       exclamation mark only if option <option>--boot</option> is
 462       given.</para>
 463
 464       <para>For example:
 465       <programlisting># Make sure these are created by default so that nobody else can
 466 d /tmp/.X11-unix 1777 root root 10d
 467
 468 # Unlink the X11 lock files
 469 r! /tmp/.X[0-9]*-lock</programlisting>
 470       The second line in contrast to the first one would break a
 471       running system, and will only be executed with
 472       <option>--boot</option>.</para>
 473
 474       <para>Note that for all line types that result in creation of any kind of file node
 475       (i.e. <varname>f</varname>/<varname>F</varname>,
 476       <varname>d</varname>/<varname>D</varname>/<varname>v</varname>/<varname>q</varname>/<varname>Q</varname>,
 477       <varname>p</varname>, <varname>L</varname>, <varname>c</varname>/<varname>b</varname> and <varname>C</varname>)
 478       leading directories are implicitly created if needed, owned by root with an access mode of 0755. In order to
 479       create them with different modes or ownership make sure to add appropriate <varname>d</varname> lines.</para>
 480     </refsect2>
 481
 482     <refsect2>
 483       <title>Path</title>
 484
 485       <para>The file system path specification supports simple
 486       specifier expansion, see below. The path (after expansion) must be
 487       absolute.</para>
 488     </refsect2>
 489
 490     <refsect2>
 491       <title>Mode</title>
 492
 493       <para>The file access mode to use when creating this file or
 494       directory. If omitted or when set to <literal>-</literal>, the
 495       default is used: 0755 for directories, 0644 for all other file
 496       objects.  For <varname>z</varname>, <varname>Z</varname> lines,
 497       if omitted or when set to <literal>-</literal>, the file access
 498       mode will not be modified. This parameter is ignored for
 499       <varname>x</varname>, <varname>r</varname>,
 500       <varname>R</varname>, <varname>L</varname>, <varname>t</varname>,
 501       and <varname>a</varname> lines.</para>
 502
 503       <para>Optionally, if prefixed with <literal>~</literal>, the
 504       access mode is masked based on the already set access bits for
 505       existing file or directories: if the existing file has all
 506       executable bits unset, all executable bits are removed from the
 507       new access mode, too. Similarly, if all read bits are removed
 508       from the old access mode, they will be removed from the new
 509       access mode too, and if all write bits are removed, they will be
 510       removed from the new access mode too. In addition, the
 511       sticky/SUID/SGID bit is removed unless applied to a
 512       directory. This functionality is particularly useful in
 513       conjunction with <varname>Z</varname>.</para>
 514     </refsect2>
 515
 516     <refsect2>
 517       <title>UID, GID</title>
 518
 519       <para>The user and group to use for this file or directory. This
 520       may either be a numeric user/group ID or a user or group
 521       name. If omitted or when set to <literal>-</literal>, the
 522       default 0 (root) is used. For <varname>z</varname> and
 523       <varname>Z</varname> lines, when omitted or when set to
 524       <literal>-</literal>, the file ownership will not be
 525       modified. These parameters are ignored for <varname>x</varname>,
 526       <varname>r</varname>, <varname>R</varname>,
 527       <varname>L</varname>, <varname>t</varname>, and
 528       <varname>a</varname> lines.</para>
 529     </refsect2>
 530
 531     <refsect2>
 532       <title>Age</title>
 533       <para>The date field, when set, is used to decide what files to
 534       delete when cleaning. If a file or directory is older than the
 535       current time minus the age field, it is deleted. The field
 536       format is a series of integers each followed by one of the
 537       following suffixes for the respective time units:
 538       <constant>s</constant>,
 539       <constant>m</constant> or <constant>min</constant>,
 540       <constant>h</constant>,
 541       <constant>d</constant>,
 542       <constant>w</constant>,
 543       <constant>ms</constant>, and
 544       <constant>us</constant>,
 545       meaning seconds, minutes, hours, days, weeks,
 546       milliseconds, and microseconds, respectively. Full names of the time units can
 547       be used too.
 548       </para>
 549
 550       <para>If multiple integers and units are specified, the time
 551       values are summed. If an integer is given without a unit,
 552       <constant>s</constant> is assumed.
 553       </para>
 554
 555       <para>When the age is set to zero, the files are cleaned
 556       unconditionally.</para>
 557
 558       <para>The age field only applies to lines starting with
 559       <varname>d</varname>, <varname>D</varname>, <varname>e</varname>,
 560       <varname>v</varname>, <varname>q</varname>,
 561       <varname>Q</varname>, <varname>C</varname>, <varname>x</varname>
 562       and <varname>X</varname>. If omitted or set to
 563       <literal>-</literal>, no automatic clean-up is done.</para>
 564
 565       <para>If the age field starts with a tilde character
 566       <literal>~</literal>, the clean-up is only applied to files and
 567       directories one level inside the directory specified, but not
 568       the files and directories immediately inside it.</para>
 569
 570       <para>The age of a file system entry is determined from its last
 571       modification timestamp (mtime), its last access timestamp (atime),
 572       and (except for directories) its last status change timestamp
 573       (ctime). Any of these three (or two) values will prevent cleanup
 574       if it is more recent than the current time minus the age
 575       field.</para>
 576     </refsect2>
 577
 578     <refsect2>
 579       <title>Argument</title>
 580
 581       <para>For <varname>L</varname> lines determines the destination path of the symlink. For <varname>c</varname> and
 582       <varname>b</varname>, determines the major/minor of the device node, with major and minor formatted as integers,
 583       separated by <literal>:</literal>, e.g.  <literal>1:3</literal>. For <varname>f</varname>, <varname>F</varname>,
 584       and <varname>w</varname>, the argument may be used to specify a short string that is written to the file,
 585       suffixed by a newline. For <varname>C</varname>, specifies the source file or directory. For <varname>t</varname>
 586       and <varname>T</varname>, determines extended attributes to be set. For <varname>a</varname> and
 587       <varname>A</varname>, determines ACL attributes to be set. For <varname>h</varname> and <varname>H</varname>,
 588       determines the file attributes to set. Ignored for all other lines.</para>
 589
 590       <para>This field can contain specifiers, see below.</para>
 591     </refsect2>
 592   </refsect1>
 593
 594   <refsect1>
 595     <title>Specifiers</title>
 596
 597     <para>Specifiers can be used in the "path" and "argument" fields.
 598     An unknown or unresolvable specifier is treated as invalid configuration.
 599     The following expansions are understood:</para>
 600       <table>
 601         <title>Specifiers available</title>
 602         <tgroup cols='3' align='left' colsep='1' rowsep='1'>
 603           <colspec colname="spec" />
 604           <colspec colname="mean" />
 605           <colspec colname="detail" />
 606           <thead>
 607             <row>
 608               <entry>Specifier</entry>
 609               <entry>Meaning</entry>
 610               <entry>Details</entry>
 611             </row>
 612           </thead>
 613           <tbody>
 614             <row>
 615               <entry><literal>%m</literal></entry>
 616               <entry>Machine ID</entry>
 617               <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
 618             </row>
 619             <row>
 620               <entry><literal>%b</literal></entry>
 621               <entry>Boot ID</entry>
 622               <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
 623             </row>
 624             <row>
 625               <entry><literal>%H</literal></entry>
 626               <entry>Host name</entry>
 627               <entry>The hostname of the running system.</entry>
 628             </row>
 629             <row>
 630               <entry><literal>%v</literal></entry>
 631               <entry>Kernel release</entry>
 632               <entry>Identical to <command>uname -r</command> output.</entry>
 633             </row>
 634             <row>
 635               <entry><literal>%U</literal></entry>
 636               <entry>User UID</entry>
 637               <entry>This is the numeric UID of the user running the service manager instance. In case of the system manager this resolves to <constant>0</constant>.</entry>
 638             </row>
 639             <row>
 640               <entry><literal>%u</literal></entry>
 641               <entry>User name</entry>
 642               <entry>This is the name of the user running the service manager instance. In case of the system manager this resolves to <literal>root</literal>.</entry>
 643             </row>
 644             <row>
 645               <entry><literal>%h</literal></entry>
 646               <entry>User home directory</entry>
 647               <entry>This is the home directory of the user running the service manager instance. In case of the system manager this resolves to <literal>/root</literal>.</entry>
 648             </row>
 649             <row>
 650               <entry><literal>%t</literal></entry>
 651               <entry>System or user runtime directory</entry>
 652               <entry>In --user mode, this is the same <varname>$XDG_RUNTIME_DIR</varname>, and <filename>/run</filename> otherwise.</entry>
 653             </row>
 654             <row>
 655               <entry><literal>%S</literal></entry>
 656               <entry>System or user state directory</entry>
 657               <entry>In <option>--user</option> mode, this is the same as <varname>$XDG_CONFIG_HOME</varname>, and <filename>/var/lib</filename> otherwise.</entry>
 658             </row>
 659             <row>
 660               <entry><literal>%C</literal></entry>
 661               <entry>System or user cache directory</entry>
 662               <entry>In <option>--user</option> mode, this is the same as <varname>$XDG_CACHE_HOME</varname>, and <filename>/var/cache</filename> otherwise.</entry>
 663             </row>
 664             <row>
 665               <entry><literal>%L</literal></entry>
 666               <entry>System or user log directory</entry>
 667               <entry>In <option>--user</option> mode, this is the same as <varname>$XDG_CONFIG_HOME</varname> with <filename noindex='true'>/log</filename> appended, and <filename>/var/log</filename> otherwise.</entry>
 668             </row>
 669             <row>
 670               <entry><literal>%%</literal></entry>
 671               <entry>Escaped <literal>%</literal></entry>
 672               <entry>Single percent sign.</entry>
 673             </row>
 674           </tbody>
 675         </tgroup>
 676       </table>
 677   </refsect1>
 678
 679   <refsect1>
 680     <title>Examples</title>
 681     <example>
 682       <title>Create directories with specific mode and ownership</title>
 683       <para>
 684       <citerefentry project='die-net'><refentrytitle>screen</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 685       needs two directories created at boot with specific modes and ownership:</para>
 686
 687       <programlisting># /usr/lib/tmpfiles.d/screen.conf
 688 d /run/screens  1777 root screen 10d
 689 d /run/uscreens 0755 root screen 10d12h
 690 </programlisting>
 691
 692       <para>Contents of <filename>/run/screens</filename> and /run/uscreens will
 693       be cleaned up after 10 and 10½ days, respectively.</para>
 694     </example>
 695
 696     <example>
 697       <title>Create a directory with a SMACK attribute</title>
 698       <programlisting>D /run/cups - - - -
 699 t /run/cups - - - - security.SMACK64=printing user.attr-with-spaces="foo bar"
 700       </programlisting>
 701
 702       <para>The directory will be owned by root and have default mode. Its contents are
 703       not subject to time based cleanup, but will be obliterated when
 704       <command>systemd-tmpfiles --remove</command> runs.</para>
 705     </example>
 706
 707     <example>
 708       <title>Create a directory and prevent its contents from cleanup</title>
 709       <para>
 710       <citerefentry project='die-net'><refentrytitle>abrt</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 711       needs a directory created at boot with specific mode and ownership and its content
 712       should be preserved from the automatic cleanup applied to the contents of
 713       <filename>/var/tmp</filename>:</para>
 714
 715       <programlisting># /usr/lib/tmpfiles.d/tmp.conf
 716 d /var/tmp 1777 root root 30d
 717 </programlisting>
 718
 719       <programlisting># /usr/lib/tmpfiles.d/abrt.conf
 720 d /var/tmp/abrt 0755 abrt abrt -
 721 </programlisting>
 722     </example>
 723
 724     <example>
 725       <title>Apply clean up during boot and based on time</title>
 726
 727       <programlisting># /usr/lib/tmpfiles.d/dnf.conf
 728 r! /var/cache/dnf/*/*/download_lock.pid
 729 r! /var/cache/dnf/*/*/metadata_lock.pid
 730 r! /var/lib/dnf/rpmdb_lock.pid
 731 e  /var/cache/dnf/ - - - 30d
 732 </programlisting>
 733
 734      <para>The lock files will be removed during boot. Any files and directories in
 735      <filename>/var/cache/dnf/</filename> will be removed after they have not been
 736      accessed in 30 days.</para>
 737     </example>
 738
 739     <example>
 740       <title>Empty the contents of a cache directory on boot</title>
 741
 742       <programlisting># /usr/lib/tmpfiles.d/krb5rcache.conf
 743 e! /var/cache/krb5rcache - - - 0
 744 </programlisting>
 745
 746       <para>Any files and subdirectories in <filename>/var/cache/krb5rcache/</filename>
 747       will be removed on boot. The directory will not be created.
 748       </para>
 749     </example>
 750   </refsect1>
 751
 752   <refsect1>
 753     <title>See Also</title>
 754     <para>
 755       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 756       <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 757       <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 758       <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 759       <citerefentry project='man-pages'><refentrytitle>attr</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 760       <citerefentry project='man-pages'><refentrytitle>getfattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 761       <citerefentry project='man-pages'><refentrytitle>setfattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 762       <citerefentry project='man-pages'><refentrytitle>setfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 763       <citerefentry project='man-pages'><refentrytitle>getfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 764       <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 765       <citerefentry project='die-net'><refentrytitle>btrfs-subvolume</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 766       <citerefentry project='die-net'><refentrytitle>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 767     </para>
 768   </refsect1>
 769
 770 </refentry>