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