man/tmpfiles.d.xml

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   8   Copyright 2010 Brandon Philips
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  23 <refentry id="tmpfiles.d">
  24
  25   <refentryinfo>
  26     <title>tmpfiles.d</title>
  27     <productname>systemd</productname>
  28
  29     <authorgroup>
  30       <author>
  31         <contrib>Documentation</contrib>
  32         <firstname>Brandon</firstname>
  33         <surname>Philips</surname>
  34         <email>brandon@ifup.org</email>
  35       </author>
  36     </authorgroup>
  37   </refentryinfo>
  38
  39   <refmeta>
  40     <refentrytitle>tmpfiles.d</refentrytitle>
  41     <manvolnum>5</manvolnum>
  42   </refmeta>
  43
  44   <refnamediv>
  45     <refname>tmpfiles.d</refname>
  46     <refpurpose>Configuration for creation, deletion and cleaning of
  47     volatile and temporary files</refpurpose>
  48   </refnamediv>
  49
  50   <refsynopsisdiv>
  51     <para><literallayout><filename>/etc/tmpfiles.d/*.conf</filename>
  52 <filename>/run/tmpfiles.d/*.conf</filename>
  53 <filename>/usr/lib/tmpfiles.d/*.conf</filename>
  54     </literallayout></para>
  55
  56     <para><literallayout><filename>~/.config/user-tmpfiles.d/*.conf</filename>
  57 <filename>$XDG_RUNTIME_DIR/user-tmpfiles.d/*.conf</filename>
  58 <filename>~/.local/share/user-tmpfiles.d/*.conf</filename>
  59 <filename>…</filename>
  60 <filename>/usr/share/user-tmpfiles.d/*.conf</filename>
  61     </literallayout></para>
  62   </refsynopsisdiv>
  63
  64   <refsect1>
  65     <title>Description</title>
  66
  67     <para><command>systemd-tmpfiles</command> uses the configuration
  68     files from the above directories to describe the creation,
  69     cleaning and removal of volatile and temporary files and
  70     directories which usually reside in directories such as
  71     <filename>/run</filename> or <filename>/tmp</filename>.</para>
  72
  73     <para>Volatile and temporary files and directories are those
  74     located in <filename>/run</filename> (and its alias
  75     <filename>/var/run</filename>), <filename>/tmp</filename>,
  76     <filename>/var/tmp</filename>, the API file systems such as
  77     <filename>/sys</filename> or <filename>/proc</filename>, as well
  78     as some other directories below <filename>/var</filename>.</para>
  79
  80     <para>System daemons frequently require private runtime
  81     directories below <filename>/run</filename> to place communication
  82     sockets and similar in. For these, consider declaring them in
  83     their unit files using <varname>RuntimeDirectory=</varname> (see
  84     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  85     for details), if this is feasible.</para>
  86   </refsect1>
  87
  88   <refsect1>
  89     <title>Configuration Directories and Precedence</title>
  90
  91     <para>Each configuration file shall be named in the style of
  92     <filename><replaceable>package</replaceable>.conf</filename> or
  93     <filename><replaceable>package</replaceable>-<replaceable>part</replaceable>.conf</filename>.
  94     The second variant should be used when it is desirable to make it
  95     easy to override just this part of configuration.</para>
  96
  97     <para>Files in <filename>/etc/tmpfiles.d</filename> override files
  98     with the same name in <filename>/usr/lib/tmpfiles.d</filename> and
  99     <filename>/run/tmpfiles.d</filename>. Files in
 100     <filename>/run/tmpfiles.d</filename> override files with the same
 101     name in <filename>/usr/lib/tmpfiles.d</filename>. Packages should
 102     install their configuration files in
 103     <filename>/usr/lib/tmpfiles.d</filename>. Files in
 104     <filename>/etc/tmpfiles.d</filename> are reserved for the local
 105     administrator, who may use this logic to override the
 106     configuration files installed by vendor packages. All
 107     configuration files are sorted by their filename in lexicographic
 108     order, regardless of which of the directories they reside in. If
 109     multiple files specify the same path, the entry in the file with
 110     the lexicographically earliest name will be applied.  All other
 111     conflicting entries will be logged as errors. When two lines are
 112     prefix and suffix of each other, then the prefix is always
 113     processed first, the suffix later. Lines that take globs are
 114     applied after those accepting no globs. If multiple operations
 115     shall be applied on the same file, (such as ACL, xattr, file
 116     attribute adjustments), these are always done in the same fixed
 117     order. Otherwise, the files/directories are processed in the order
 118     they are listed.</para>
 119
 120     <para>If the administrator wants to disable a configuration file
 121     supplied by the vendor, the recommended way is to place a symlink
 122     to <filename>/dev/null</filename> in
 123     <filename>/etc/tmpfiles.d/</filename> bearing the same filename.
 124     </para>
 125   </refsect1>
 126
 127   <refsect1>
 128     <title>Configuration File Format</title>
 129
 130     <para>The configuration format is one line per path containing
 131     type, path, mode, ownership, age, and argument fields:</para>
 132
 133     <programlisting>#Type Path        Mode UID  GID  Age Argument
 134 d     /run/user   0755 root root 10d -
 135 L     /tmp/foobar -    -    -    -   /dev/null</programlisting>
 136
 137     <para>Fields may be enclosed within quotes and contain C-style escapes.</para>
 138
 139     <refsect2>
 140       <title>Type</title>
 141
 142       <para>The type consists of a single letter and optionally an
 143       exclamation mark.</para>
 144
 145       <para>The following line types are understood:</para>
 146
 147       <variablelist>
 148         <varlistentry>
 149           <term><varname>f</varname></term>
 150           <listitem><para>Create a file if it does not exist yet. If
 151           the argument parameter is given, it will be written to the
 152           file. Does not follow symlinks.</para></listitem>
 153         </varlistentry>
 154
 155         <varlistentry>
 156           <term><varname>F</varname></term>
 157           <listitem><para>Create or truncate a file. If the argument
 158           parameter is given, it will be written to the file. Does not follow symlinks.</para>
 159           </listitem>
 160         </varlistentry>
 161
 162         <varlistentry>
 163           <term><varname>w</varname></term>
 164           <listitem><para>Write the argument parameter to a file, if
 165           the file exists.  Lines of this type accept shell-style
 166           globs in place of normal path names. The argument parameter
 167           will be written without a trailing newline. C-style
 168           backslash escapes are interpreted. Follows
 169           symlinks.</para></listitem>
 170         </varlistentry>
 171
 172         <varlistentry>
 173           <term><varname>d</varname></term>
 174           <listitem><para>Create a directory. The mode and ownership will be adjusted if
 175           specified and the directory already exists. Contents of this directory are subject
 176           to time based cleanup if the age argument is specified.</para></listitem>
 177         </varlistentry>
 178
 179         <varlistentry>
 180           <term><varname>D</varname></term>
 181           <listitem><para>Similar to <varname>d</varname>, but in addition the contents
 182           of the directory will be removed when <option>--remove</option> is used.
 183           </para></listitem>
 184         </varlistentry>
 185
 186         <varlistentry>
 187           <term><varname>e</varname></term>
 188           <listitem><para>Similar to <varname>d</varname>, but the directory will not be created if
 189           it does not exist. Lines of this type accept shell-style globs in place of normal path
 190           names. For this entry to be useful, at least one of the mode, uid, gid, or age arguments
 191           must be specified, since otherwise this entry has no effect. If the age argument is
 192           <literal>0</literal>, contents of the directory will be unconditionally deleted every time
 193           <command>systemd-tmpfiles --clean</command> is run. This can be useful when combined with
 194           <varname>!</varname>, see the examples.</para></listitem>
 195         </varlistentry>
 196
 197         <varlistentry>
 198           <term><varname>v</varname></term>
 199           <listitem><para>Create a subvolume if the path does not
 200           exist yet, the file system supports subvolumes (btrfs), and
 201           the system itself is installed into a subvolume
 202           (specifically: the root directory <filename>/</filename> is
 203           itself a subvolume). Otherwise, create a normal directory, in
 204           the same way as <varname>d</varname>. A subvolume created
 205           with this line type is not assigned to any higher-level
 206           quota group. For that, use <varname>q</varname> or
 207           <varname>Q</varname>, which allow creating simple quota
 208           group hierarchies, see below.</para></listitem>
 209         </varlistentry>
 210
 211         <varlistentry>
 212           <term><varname>q</varname></term>
 213           <listitem><para>Similar to <varname>v</varname>. However,
 214           makes sure that the subvolume will be assigned to the same
 215           higher-level quota groups as the subvolume it has been
 216           created in. This ensures that higher-level limits and
 217           accounting applied to the parent subvolume also include the
 218           specified subvolume. On non-btrfs file systems, this line
 219           type is identical to <varname>d</varname>. If the subvolume
 220           already exists and is already assigned to one or more higher
 221           level quota groups, no change to the quota hierarchy is
 222           made. Also see <varname>Q</varname> below. See <citerefentry
 223           project='die-net'><refentrytitle>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 224           for details about the btrfs quota group
 225           concept.</para></listitem>
 226         </varlistentry>
 227
 228         <varlistentry>
 229           <term><varname>Q</varname></term>
 230           <listitem><para>Similar to <varname>q</varname>. However,
 231           instead of copying the higher-level quota group assignments
 232           from the parent as-is, the lowest quota group of the parent
 233           subvolume is determined that is not the leaf quota
 234           group. Then, an "intermediary" quota group is inserted that
 235           is one level below this level, and shares the same ID part
 236           as the specified subvolume. If no higher-level quota group
 237           exists for the parent subvolume, a new quota group at level
 238           255 sharing the same ID as the specified subvolume is
 239           inserted instead. This new intermediary quota group is then
 240           assigned to the parent subvolume's higher-level quota
 241           groups, and the specified subvolume's leaf quota group is
 242           assigned to it.</para>
 243
 244           <para>Effectively, this has a similar effect as
 245           <varname>q</varname>, however introduces a new higher-level
 246           quota group for the specified subvolume that may be used to
 247           enforce limits and accounting to the specified subvolume and
 248           children subvolume created within it. Thus, by creating
 249           subvolumes only via <varname>q</varname> and
 250           <varname>Q</varname>, a concept of "subtree quotas" is
 251           implemented. Each subvolume for which <varname>Q</varname>
 252           is set will get a "subtree" quota group created, and all
 253           child subvolumes created within it will be assigned to
 254           it. Each subvolume for which <varname>q</varname> is set
 255           will not get such a "subtree" quota group, but it is ensured
 256           that they are added to the same "subtree" quota group as their
 257           immediate parents.</para>
 258
 259           <para>It is recommended to use
 260           <varname>Q</varname> for subvolumes that typically contain
 261           further subvolumes, and where it is desirable to have
 262           accounting and quota limits on all child subvolumes
 263           together. Examples for <varname>Q</varname> are typically
 264           <filename>/home</filename> or
 265           <filename>/var/lib/machines</filename>. In contrast,
 266           <varname>q</varname> should be used for subvolumes that
 267           either usually do not include further subvolumes or where no
 268           accounting and quota limits are needed that apply to all
 269           child subvolumes together. Examples for <varname>q</varname>
 270           are typically <filename>/var</filename> or
 271           <filename>/var/tmp</filename>. As with <varname>Q</varname>,
 272           <varname>q</varname> has no effect on the quota group
 273           hierarchy if the subvolume exists and already has at least
 274           one higher-level quota group assigned.</para></listitem>
 275         </varlistentry>
 276
 277         <varlistentry>
 278           <term><varname>p</varname></term>
 279           <term><varname>p+</varname></term>
 280           <listitem><para>Create a named pipe (FIFO) if it does not
 281           exist yet. If suffixed with <varname>+</varname> and a file
 282           already exists where the pipe is to be created, it will be
 283           removed and be replaced by the pipe.</para></listitem>
 284         </varlistentry>
 285
 286         <varlistentry>
 287           <term><varname>L</varname></term>
 288           <term><varname>L+</varname></term>
 289           <listitem><para>Create a symlink if it does not exist
 290           yet. If suffixed with <varname>+</varname> and a file or
 291           directory already exists where the symlink is to be created,
 292           it will be removed and be replaced by the symlink. If the
 293           argument is omitted, symlinks to files with the same name
 294           residing in the directory
 295           <filename>/usr/share/factory/</filename> are created. Note
 296           that permissions and ownership on symlinks are ignored.
 297           </para></listitem>
 298         </varlistentry>
 299
 300         <varlistentry>
 301           <term><varname>c</varname></term>
 302           <term><varname>c+</varname></term>
 303           <listitem><para>Create a character device node if it does
 304           not exist yet. If suffixed with <varname>+</varname> and a
 305           file already exists where the device node is to be created,
 306           it will be removed and be replaced by the device node. It is
 307           recommended to suffix this entry with an exclamation mark to
 308           only create static device nodes at boot, as udev will not
 309           manage static device nodes that are created at runtime.
 310           </para></listitem>
 311         </varlistentry>
 312
 313         <varlistentry>
 314           <term><varname>b</varname></term>
 315           <term><varname>b+</varname></term>
 316           <listitem><para>Create a block device node if it does not
 317           exist yet. If suffixed with <varname>+</varname> and a file
 318           already exists where the device node is to be created, it
 319           will be removed and be replaced by the device node. It is
 320           recommended to suffix this entry with an exclamation mark to
 321           only create static device nodes at boot, as udev will not
 322           manage static device nodes that are created at runtime.
 323           </para></listitem>
 324         </varlistentry>
 325
 326         <varlistentry>
 327           <term><varname>C</varname></term>
 328           <listitem><para>Recursively copy a file or directory, if the
 329           destination files or directories do not exist yet. Note that
 330           this command will not descend into subdirectories if the
 331           destination directory already exists. Instead, the entire
 332           copy operation is skipped. If the argument is omitted, files
 333           from the source directory
 334           <filename>/usr/share/factory/</filename> with the same name
 335           are copied. Does not follow symlinks.</para></listitem>
 336         </varlistentry>
 337
 338         <varlistentry>
 339           <term><varname>x</varname></term>
 340           <listitem><para>Ignore a path during cleaning. Use this type
 341           to exclude paths from clean-up as controlled with the Age
 342           parameter. Note that lines of this type do not influence the
 343           effect of <varname>r</varname> or <varname>R</varname>
 344           lines. Lines of this type accept shell-style globs in place
 345           of normal path names.  </para></listitem>
 346         </varlistentry>
 347
 348         <varlistentry>
 349           <term><varname>X</varname></term>
 350           <listitem><para>Ignore a path during cleaning. Use this type
 351           to exclude paths from clean-up as controlled with the Age
 352           parameter. Unlike <varname>x</varname>, this parameter will
 353           not exclude the content if path is a directory, but only
 354           directory itself. Note that lines of this type do not
 355           influence the effect of <varname>r</varname> or
 356           <varname>R</varname> lines. Lines of this type accept
 357           shell-style globs in place of normal path names.
 358           </para></listitem>
 359         </varlistentry>
 360
 361         <varlistentry>
 362           <term><varname>r</varname></term>
 363           <listitem><para>Remove a file or directory if it exists.
 364           This may not be used to remove non-empty directories, use
 365           <varname>R</varname> for that.  Lines of this type accept
 366           shell-style globs in place of normal path
 367           names. Does not follow symlinks.</para></listitem>
 368         </varlistentry>
 369
 370         <varlistentry>
 371           <term><varname>R</varname></term>
 372           <listitem><para>Recursively remove a path and all its
 373           subdirectories (if it is a directory). Lines of this type
 374           accept shell-style globs in place of normal path
 375           names. Does not follow symlinks.</para></listitem>
 376         </varlistentry>
 377
 378         <varlistentry>
 379           <term><varname>z</varname></term>
 380           <listitem><para>Adjust the access mode, group and user, and
 381           restore the SELinux security context of a file or directory,
 382           if it exists. Lines of this type accept shell-style globs in
 383           place of normal path names. Does not follow symlinks.</para></listitem>
 384         </varlistentry>
 385
 386         <varlistentry>
 387           <term><varname>Z</varname></term>
 388           <listitem><para>Recursively set the access mode, group and
 389           user, and restore the SELinux security context of a file or
 390           directory if it exists, as well as of its subdirectories and
 391           the files contained therein (if applicable). Lines of this
 392           type accept shell-style globs in place of normal path
 393           names. Does not follow symlinks.  </para></listitem>
 394         </varlistentry>
 395
 396         <varlistentry>
 397           <term><varname>t</varname></term>
 398           <listitem><para>Set extended attributes. Lines of this type
 399           accept shell-style globs in place of normal path names.
 400           This can be useful for setting SMACK labels. Does not follow
 401           symlinks.</para></listitem>
 402         </varlistentry>
 403
 404         <varlistentry>
 405           <term><varname>T</varname></term>
 406           <listitem><para>Recursively set extended attributes. Lines
 407           of this type accept shell-style globs in place of normal
 408           path names.  This can be useful for setting SMACK
 409           labels. Does not follow symlinks.  </para></listitem>
 410         </varlistentry>
 411
 412         <varlistentry>
 413           <term><varname>h</varname></term>
 414           <listitem><para>Set file/directory attributes. Lines of this type
 415           accept shell-style globs in place of normal path names.</para>
 416
 417           <para>The format of the argument field is
 418           <varname>[+-=][aAcCdDeijsStTu] </varname>. The prefix
 419           <varname>+</varname> (the default one) causes the
 420           attribute(s) to be added; <varname>-</varname> causes the
 421           attribute(s) to be removed; <varname>=</varname> causes the
 422           attributes to be set exactly as the following letters. The
 423           letters <literal>aAcCdDeijsStTu</literal> select the new
 424           attributes for the files, see
 425           <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle>
 426           <manvolnum>1</manvolnum></citerefentry> for further information.
 427           </para>
 428           <para>Passing only <varname>=</varname> as argument resets
 429           all the file attributes listed above. It has to be pointed
 430           out that the <varname>=</varname> prefix limits itself to
 431           the attributes corresponding to the letters listed here. All
 432           other attributes will be left untouched. Does not follow
 433           symlinks.</para>
 434           </listitem>
 435         </varlistentry>
 436
 437         <varlistentry>
 438           <term><varname>H</varname></term>
 439           <listitem><para>Recursively set file/directory attributes. Lines
 440           of this type accept shell-style globs in place of normal
 441           path names. Does not follow symlinks.
 442           </para></listitem>
 443         </varlistentry>
 444
 445         <varlistentry>
 446           <term><varname>a</varname></term>
 447           <term><varname>a+</varname></term>
 448           <listitem><para>Set POSIX ACLs (access control lists). If
 449           suffixed with <varname>+</varname>, the specified entries will
 450           be added to the existing set.
 451           <command>systemd-tmpfiles</command> will automatically add
 452           the required base entries for user and group based on the
 453           access mode of the file, unless base entries already exist
 454           or are explicitly specified. The mask will be added if not
 455           specified explicitly or already present. Lines of this type
 456           accept shell-style globs in place of normal path names. This
 457           can be useful for allowing additional access to certain
 458           files. Does not follow symlinks.</para></listitem>
 459         </varlistentry>
 460
 461         <varlistentry>
 462           <term><varname>A</varname></term>
 463           <term><varname>A+</varname></term>
 464           <listitem><para>Same as <varname>a</varname> and
 465           <varname>a+</varname>, but recursive. Does not follow
 466           symlinks.</para></listitem>
 467         </varlistentry>
 468       </variablelist>
 469
 470       <para>If the exclamation mark is used, this line is only safe of
 471       execute during boot, and can break a running system. Lines
 472       without the exclamation mark are presumed to be safe to execute
 473       at any time, e.g. on package upgrades.
 474       <command>systemd-tmpfiles</command> will execute line with an
 475       exclamation mark only if option <option>--boot</option> is
 476       given.</para>
 477
 478       <para>For example:
 479       <programlisting># Make sure these are created by default so that nobody else can
 480 d /tmp/.X11-unix 1777 root root 10d
 481
 482 # Unlink the X11 lock files
 483 r! /tmp/.X[0-9]*-lock</programlisting>
 484       The second line in contrast to the first one would break a
 485       running system, and will only be executed with
 486       <option>--boot</option>.</para>
 487     </refsect2>
 488
 489     <refsect2>
 490       <title>Path</title>
 491
 492       <para>The file system path specification supports simple
 493       specifier expansion, see below. The path (after expansion) must be
 494       absolute.</para>
 495     </refsect2>
 496
 497     <refsect2>
 498       <title>Mode</title>
 499
 500       <para>The file access mode to use when creating this file or
 501       directory. If omitted or when set to <literal>-</literal>, the
 502       default is used: 0755 for directories, 0644 for all other file
 503       objects.  For <varname>z</varname>, <varname>Z</varname> lines,
 504       if omitted or when set to <literal>-</literal>, the file access
 505       mode will not be modified. This parameter is ignored for
 506       <varname>x</varname>, <varname>r</varname>,
 507       <varname>R</varname>, <varname>L</varname>, <varname>t</varname>,
 508       and <varname>a</varname> lines.</para>
 509
 510       <para>Optionally, if prefixed with <literal>~</literal>, the
 511       access mode is masked based on the already set access bits for
 512       existing file or directories: if the existing file has all
 513       executable bits unset, all executable bits are removed from the
 514       new access mode, too. Similarly, if all read bits are removed
 515       from the old access mode, they will be removed from the new
 516       access mode too, and if all write bits are removed, they will be
 517       removed from the new access mode too. In addition, the
 518       sticky/SUID/SGID bit is removed unless applied to a
 519       directory. This functionality is particularly useful in
 520       conjunction with <varname>Z</varname>.</para>
 521     </refsect2>
 522
 523     <refsect2>
 524       <title>UID, GID</title>
 525
 526       <para>The user and group to use for this file or directory. This
 527       may either be a numeric user/group ID or a user or group
 528       name. If omitted or when set to <literal>-</literal>, the
 529       default 0 (root) is used. For <varname>z</varname> and
 530       <varname>Z</varname> lines, when omitted or when set to
 531       <literal>-</literal>, the file ownership will not be
 532       modified. These parameters are ignored for <varname>x</varname>,
 533       <varname>r</varname>, <varname>R</varname>,
 534       <varname>L</varname>, <varname>t</varname>, and
 535       <varname>a</varname> lines.</para>
 536     </refsect2>
 537
 538     <refsect2>
 539       <title>Age</title>
 540       <para>The date field, when set, is used to decide what files to
 541       delete when cleaning. If a file or directory is older than the
 542       current time minus the age field, it is deleted. The field
 543       format is a series of integers each followed by one of the
 544       following suffixes for the respective time units:
 545       <constant>s</constant>,
 546       <constant>m</constant> or <constant>min</constant>,
 547       <constant>h</constant>,
 548       <constant>d</constant>,
 549       <constant>w</constant>,
 550       <constant>ms</constant>, and
 551       <constant>us</constant>,
 552       meaning seconds, minutes, hours, days, weeks,
 553       milliseconds, and microseconds, respectively. Full names of the time units can
 554       be used too.
 555       </para>
 556
 557       <para>If multiple integers and units are specified, the time
 558       values are summed. If an integer is given without a unit,
 559       <constant>s</constant> is assumed.
 560       </para>
 561
 562       <para>When the age is set to zero, the files are cleaned
 563       unconditionally.</para>
 564
 565       <para>The age field only applies to lines starting with
 566       <varname>d</varname>, <varname>D</varname>, <varname>e</varname>,
 567       <varname>v</varname>, <varname>q</varname>,
 568       <varname>Q</varname>, <varname>C</varname>, <varname>x</varname>
 569       and <varname>X</varname>. If omitted or set to
 570       <literal>-</literal>, no automatic clean-up is done.</para>
 571
 572       <para>If the age field starts with a tilde character
 573       <literal>~</literal>, the clean-up is only applied to files and
 574       directories one level inside the directory specified, but not
 575       the files and directories immediately inside it.</para>
 576     </refsect2>
 577
 578     <refsect2>
 579       <title>Argument</title>
 580
 581       <para>For <varname>L</varname> lines determines the destination
 582       path of the symlink. For <varname>c</varname> and
 583       <varname>b</varname>, determines the major/minor of the device
 584       node, with major and minor formatted as integers, separated by
 585       <literal>:</literal>, e.g.  <literal>1:3</literal>. For
 586       <varname>f</varname>, <varname>F</varname>, and
 587       <varname>w</varname>, the argument may be used to specify a short string that
 588       is written to the file, suffixed by a newline. For
 589       <varname>C</varname>, specifies the source file or
 590       directory. For <varname>t</varname> and <varname>T</varname>,
 591       determines extended attributes to be set. For
 592       <varname>a</varname> and <varname>A</varname>, determines ACL
 593       attributes to be set. For <varname>h</varname> and
 594       <varname>H</varname>, determines the file attributes to
 595       set. Ignored for all other lines.</para>
 596
 597       <para>This field can contain specifiers, see below.</para>
 598     </refsect2>
 599   </refsect1>
 600
 601   <refsect1>
 602     <title>Specifiers</title>
 603
 604     <para>Specifiers can be used in the "path" and "argument" fields.
 605     An unknown or unresolvable specifier is treated as invalid configuration.
 606     The following expansions are understood:</para>
 607       <table>
 608         <title>Specifiers available</title>
 609         <tgroup cols='3' align='left' colsep='1' rowsep='1'>
 610           <colspec colname="spec" />
 611           <colspec colname="mean" />
 612           <colspec colname="detail" />
 613           <thead>
 614             <row>
 615               <entry>Specifier</entry>
 616               <entry>Meaning</entry>
 617               <entry>Details</entry>
 618             </row>
 619           </thead>
 620           <tbody>
 621             <row>
 622               <entry><literal>%m</literal></entry>
 623               <entry>Machine ID</entry>
 624               <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>
 625             </row>
 626             <row>
 627               <entry><literal>%b</literal></entry>
 628               <entry>Boot ID</entry>
 629               <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
 630             </row>
 631             <row>
 632               <entry><literal>%H</literal></entry>
 633               <entry>Host name</entry>
 634               <entry>The hostname of the running system.</entry>
 635             </row>
 636             <row>
 637               <entry><literal>%v</literal></entry>
 638               <entry>Kernel release</entry>
 639               <entry>Identical to <command>uname -r</command> output.</entry>
 640             </row>
 641             <row>
 642               <entry><literal>%U</literal></entry>
 643               <entry>User UID</entry>
 644               <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>
 645             </row>
 646             <row>
 647               <entry><literal>%u</literal></entry>
 648               <entry>User name</entry>
 649               <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>
 650             </row>
 651             <row>
 652               <entry><literal>%h</literal></entry>
 653               <entry>User home directory</entry>
 654               <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>
 655             </row>
 656             <row>
 657               <entry><literal>%t</literal></entry>
 658               <entry>System or user runtime directory</entry>
 659               <entry>In --user mode, this is the same <varname>$XDG_RUNTIME_DIR</varname>, and <filename>/run</filename> otherwise.</entry>
 660             </row>
 661             <row>
 662               <entry><literal>%S</literal></entry>
 663               <entry>System or user state directory</entry>
 664               <entry>In <option>--user</option> mode, this is the same as <varname>$XDG_CONFIG_HOME</varname>, and <filename>/var/lib</filename> otherwise.</entry>
 665             </row>
 666             <row>
 667               <entry><literal>%C</literal></entry>
 668               <entry>System or user cache directory</entry>
 669               <entry>In <option>--user</option> mode, this is the same as <varname>$XDG_CACHE_HOME</varname>, and <filename>/var/cache</filename> otherwise.</entry>
 670             </row>
 671             <row>
 672               <entry><literal>%L</literal></entry>
 673               <entry>System or user log directory</entry>
 674               <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>
 675             </row>
 676             <row>
 677               <entry><literal>%%</literal></entry>
 678               <entry>Escaped <literal>%</literal></entry>
 679               <entry>Single percent sign.</entry>
 680             </row>
 681           </tbody>
 682         </tgroup>
 683       </table>
 684   </refsect1>
 685
 686   <refsect1>
 687     <title>Examples</title>
 688     <example>
 689       <title>Create directories with specific mode and ownership</title>
 690       <para>
 691       <citerefentry project='die-net'><refentrytitle>screen</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 692       needs two directories created at boot with specific modes and ownership:</para>
 693
 694       <programlisting># /usr/lib/tmpfiles.d/screen.conf
 695 d /run/screens  1777 root screen 10d
 696 d /run/uscreens 0755 root screen 10d12h
 697 </programlisting>
 698
 699       <para>Contents of <filename>/run/screens</filename> and /run/uscreens will
 700       cleaned up after 10 and 10½ days, respectively.</para>
 701     </example>
 702
 703     <example>
 704       <title>Create a directory with a SMACK attribute</title>
 705       <programlisting>D /run/cups - - - -
 706 t /run/cups - - - - security.SMACK64=printing user.attr-with-spaces="foo bar"
 707       </programlisting>
 708
 709       <para>The directory will be owned by root and have default mode. Its contents are
 710       not subject to time based cleanup, but will be obliterated when
 711       <command>systemd-tmpfiles --remove</command> runs.</para>
 712     </example>
 713
 714     <example>
 715       <title>Create a directory and prevent its contents from cleanup</title>
 716       <para>
 717       <citerefentry project='die-net'><refentrytitle>abrt</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 718       needs a directory created at boot with specific mode and ownership and its content
 719       should be preserved from the automatic cleanup applied to the contents of
 720       <filename>/var/tmp</filename>:</para>
 721
 722       <programlisting># /usr/lib/tmpfiles.d/tmp.conf
 723 d /var/tmp 1777 root root 30d
 724 </programlisting>
 725
 726       <programlisting># /usr/lib/tmpfiles.d/abrt.conf
 727 d /var/tmp/abrt 0755 abrt abrt -
 728 </programlisting>
 729     </example>
 730
 731     <example>
 732       <title>Apply clean up during boot and based on time</title>
 733
 734       <programlisting># /usr/lib/tmpfiles.d/dnf.conf
 735 r! /var/cache/dnf/*/*/download_lock.pid
 736 r! /var/cache/dnf/*/*/metadata_lock.pid
 737 r! /var/lib/dnf/rpmdb_lock.pid
 738 e  /var/cache/dnf/ - - - 30d
 739 </programlisting>
 740
 741      <para>The lock files will be removed during boot. Any files and directories in
 742      <filename>/var/cache/dnf/</filename> will be removed after they have not been
 743      accessed in 30 days.</para>
 744     </example>
 745
 746     <example>
 747       <title>Empty the contents of a cache directory on boot</title>
 748
 749       <programlisting># /usr/lib/tmpfiles.d/krb5rcache.conf
 750 e! /var/cache/krb5rcache - - - 0
 751 </programlisting>
 752
 753       <para>Any files and subdirectories in <filename>/var/cache/krb5rcache/</filename>
 754       will be removed on boot. The directory will not be created.
 755       </para>
 756     </example>
 757   </refsect1>
 758
 759   <refsect1>
 760     <title>See Also</title>
 761     <para>
 762       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 763       <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 764       <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 765       <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 766       <citerefentry project='man-pages'><refentrytitle>attr</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 767       <citerefentry project='man-pages'><refentrytitle>getfattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 768       <citerefentry project='man-pages'><refentrytitle>setfattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 769       <citerefentry project='man-pages'><refentrytitle>setfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 770       <citerefentry project='man-pages'><refentrytitle>getfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 771       <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 772       <citerefentry project='die-net'><refentrytitle>btrfs-subvolume</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 773       <citerefentry project='die-net'><refentrytitle>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 774     </para>
 775   </refsect1>
 776
 777 </refentry>