tmpfiles.d — Configuration for creation, deletion and cleaning of volatile and temporary files
/etc/tmpfiles.d/*.conf
/run/tmpfiles.d/*.conf
/usr/lib/tmpfiles.d/*.conf
~/.config/user-tmpfiles.d/*.conf
$XDG_RUNTIME_DIR/user-tmpfiles.d/*.conf
~/.local/share/user-tmpfiles.d/*.conf
…
/usr/share/user-tmpfiles.d/*.conf
systemd-tmpfiles uses the configuration
files from the above directories to describe the creation,
cleaning and removal of volatile and temporary files and
directories which usually reside in directories such as
/run or /tmp.
Volatile and temporary files and directories are those
located in /run (and its alias
/var/run), /tmp,
/var/tmp, the API file systems such as
/sys or /proc, as well
as some other directories below /var.
System daemons frequently require private runtime
directories below /run to place communication
sockets and similar in. For these, consider declaring them in
their unit files using RuntimeDirectory= (see
systemd.exec(5)
for details), if this is feasible.
Each configuration file shall be named in the style of
package.confpackage-part.conf
Files in /etc/tmpfiles.d override files
with the same name in /usr/lib/tmpfiles.d and
/run/tmpfiles.d. Files in
/run/tmpfiles.d override files with the same
name in /usr/lib/tmpfiles.d. Packages should
install their configuration files in
/usr/lib/tmpfiles.d. Files in
/etc/tmpfiles.d are reserved for the local
administrator, who may use this logic to override the
configuration files installed by vendor packages. All
configuration files are sorted by their filename in lexicographic
order, regardless of which of the directories they reside in. If
multiple files specify the same path, the entry in the file with
the lexicographically earliest name will be applied. All other
conflicting entries will be logged as errors. When two lines are
prefix and suffix of each other, then the prefix is always
processed first, the suffix later. Lines that take globs are
applied after those accepting no globs. If multiple operations
shall be applied on the same file, (such as ACL, xattr, file
attribute adjustments), these are always done in the same fixed
order. Otherwise, the files/directories are processed in the order
they are listed.
If the administrator wants to disable a configuration file
supplied by the vendor, the recommended way is to place a symlink
to /dev/null in
/etc/tmpfiles.d/ bearing the same filename.
The configuration format is one line per path containing type, path, mode, ownership, age, and argument fields:
#Type Path Mode UID GID Age Argument d /run/user 0755 root root 10d - L /tmp/foobar - - - - /dev/null
Fields may be enclosed within quotes and contain C-style escapes.
The type consists of a single letter and optionally an exclamation mark.
The following line types are understood:
f¶Create a file if it does not exist yet. If the argument parameter is given and the file did not exist yet, it will be written to the file. Does not follow symlinks.
F¶Create or truncate a file. If the argument parameter is given, it will be written to the file. Does not follow symlinks.
w¶Write the argument parameter to a file, if the file exists. Lines of this type accept shell-style globs in place of normal path names. The argument parameter will be written without a trailing newline. C-style backslash escapes are interpreted. Follows symlinks.
d¶Create a directory. The mode and ownership will be adjusted if specified and the directory already exists. Contents of this directory are subject to time based cleanup if the age argument is specified.
D¶Similar to d, but in addition the contents
of the directory will be removed when --remove is used.
e¶Similar to d, but the directory will not be created if
it does not exist. Lines of this type accept shell-style globs in place of normal path
names. For this entry to be useful, at least one of the mode, uid, gid, or age arguments
must be specified, since otherwise this entry has no effect. If the age argument is
"0", contents of the directory will be unconditionally deleted every time
systemd-tmpfiles --clean is run. This can be useful when combined with
!, see the examples.
v¶Create a subvolume if the path does not
exist yet, the file system supports subvolumes (btrfs), and
the system itself is installed into a subvolume
(specifically: the root directory / is
itself a subvolume). Otherwise, create a normal directory, in
the same way as d. A subvolume created
with this line type is not assigned to any higher-level
quota group. For that, use q or
Q, which allow creating simple quota
group hierarchies, see below.
q¶Similar to v. However,
makes sure that the subvolume will be assigned to the same
higher-level quota groups as the subvolume it has been
created in. This ensures that higher-level limits and
accounting applied to the parent subvolume also include the
specified subvolume. On non-btrfs file systems, this line
type is identical to d. If the subvolume
already exists and is already assigned to one or more higher
level quota groups, no change to the quota hierarchy is
made. Also see Q below. See btrfs-qgroup(8)
for details about the btrfs quota group
concept.
Q¶Similar to q. However,
instead of copying the higher-level quota group assignments
from the parent as-is, the lowest quota group of the parent
subvolume is determined that is not the leaf quota
group. Then, an "intermediary" quota group is inserted that
is one level below this level, and shares the same ID part
as the specified subvolume. If no higher-level quota group
exists for the parent subvolume, a new quota group at level
255 sharing the same ID as the specified subvolume is
inserted instead. This new intermediary quota group is then
assigned to the parent subvolume's higher-level quota
groups, and the specified subvolume's leaf quota group is
assigned to it.
Effectively, this has a similar effect as
q, however introduces a new higher-level
quota group for the specified subvolume that may be used to
enforce limits and accounting to the specified subvolume and
children subvolume created within it. Thus, by creating
subvolumes only via q and
Q, a concept of "subtree quotas" is
implemented. Each subvolume for which Q
is set will get a "subtree" quota group created, and all
child subvolumes created within it will be assigned to
it. Each subvolume for which q is set
will not get such a "subtree" quota group, but it is ensured
that they are added to the same "subtree" quota group as their
immediate parents.
It is recommended to use
Q for subvolumes that typically contain
further subvolumes, and where it is desirable to have
accounting and quota limits on all child subvolumes
together. Examples for Q are typically
/home or
/var/lib/machines. In contrast,
q should be used for subvolumes that
either usually do not include further subvolumes or where no
accounting and quota limits are needed that apply to all
child subvolumes together. Examples for q
are typically /var or
/var/tmp. As with Q,
q has no effect on the quota group
hierarchy if the subvolume exists and already has at least
one higher-level quota group assigned.
p, p+¶Create a named pipe (FIFO) if it does not
exist yet. If suffixed with + and a file
already exists where the pipe is to be created, it will be
removed and be replaced by the pipe.
L, L+¶Create a symlink if it does not exist
yet. If suffixed with + and a file or
directory already exists where the symlink is to be created,
it will be removed and be replaced by the symlink. If the
argument is omitted, symlinks to files with the same name
residing in the directory
/usr/share/factory/ are created. Note
that permissions and ownership on symlinks are ignored.
c, c+¶Create a character device node if it does
not exist yet. If suffixed with + and a
file already exists where the device node is to be created,
it will be removed and be replaced by the device node. It is
recommended to suffix this entry with an exclamation mark to
only create static device nodes at boot, as udev will not
manage static device nodes that are created at runtime.
b, b+¶Create a block device node if it does not
exist yet. If suffixed with + and a file
already exists where the device node is to be created, it
will be removed and be replaced by the device node. It is
recommended to suffix this entry with an exclamation mark to
only create static device nodes at boot, as udev will not
manage static device nodes that are created at runtime.
C¶Recursively copy a file or directory, if the
destination files or directories do not exist yet. Note that
this command will not descend into subdirectories if the
destination directory already exists. Instead, the entire
copy operation is skipped. If the argument is omitted, files
from the source directory
/usr/share/factory/ with the same name
are copied. Does not follow symlinks.
x¶Ignore a path during cleaning. Use this type
to exclude paths from clean-up as controlled with the Age
parameter. Note that lines of this type do not influence the
effect of r or R
lines. Lines of this type accept shell-style globs in place
of normal path names.
X¶Ignore a path during cleaning. Use this type
to exclude paths from clean-up as controlled with the Age
parameter. Unlike x, this parameter will
not exclude the content if path is a directory, but only
directory itself. Note that lines of this type do not
influence the effect of r or
R lines. Lines of this type accept
shell-style globs in place of normal path names.
r¶Remove a file or directory if it exists.
This may not be used to remove non-empty directories, use
R for that. Lines of this type accept
shell-style globs in place of normal path
names. Does not follow symlinks.
R¶Recursively remove a path and all its subdirectories (if it is a directory). Lines of this type accept shell-style globs in place of normal path names. Does not follow symlinks.
z¶Adjust the access mode, group and user, and restore the SELinux security context of a file or directory, if it exists. Lines of this type accept shell-style globs in place of normal path names. Does not follow symlinks.
Z¶Recursively set the access mode, group and user, and restore the SELinux security context of a file or directory if it exists, as well as of its subdirectories and the files contained therein (if applicable). Lines of this type accept shell-style globs in place of normal path names. Does not follow symlinks.
t¶Set extended attributes. Lines of this type accept shell-style globs in place of normal path names. This can be useful for setting SMACK labels. Does not follow symlinks.
T¶Recursively set extended attributes. Lines of this type accept shell-style globs in place of normal path names. This can be useful for setting SMACK labels. Does not follow symlinks.
h¶Set file/directory attributes. Lines of this type accept shell-style globs in place of normal path names.
The format of the argument field is
[+-=][aAcCdDeijsStTu] . The prefix
+ (the default one) causes the
attribute(s) to be added; - causes the
attribute(s) to be removed; = causes the
attributes to be set exactly as the following letters. The
letters "aAcCdDeijsStTu" select the new
attributes for the files, see
chattr(1) for further information.
Passing only = as argument resets
all the file attributes listed above. It has to be pointed
out that the = prefix limits itself to
the attributes corresponding to the letters listed here. All
other attributes will be left untouched. Does not follow
symlinks.
H¶Recursively set file/directory attributes. Lines of this type accept shell-style globs in place of normal path names. Does not follow symlinks.
a, a+¶Set POSIX ACLs (access control lists). If
suffixed with +, the specified entries will
be added to the existing set.
systemd-tmpfiles will automatically add
the required base entries for user and group based on the
access mode of the file, unless base entries already exist
or are explicitly specified. The mask will be added if not
specified explicitly or already present. Lines of this type
accept shell-style globs in place of normal path names. This
can be useful for allowing additional access to certain
files. Does not follow symlinks.
A, A+¶Same as a and
a+, but recursive. Does not follow
symlinks.
If the exclamation mark is used, this line is only safe of
execute during boot, and can break a running system. Lines
without the exclamation mark are presumed to be safe to execute
at any time, e.g. on package upgrades.
systemd-tmpfiles will execute line with an
exclamation mark only if option --boot is
given.
For example:
# Make sure these are created by default so that nobody else can d /tmp/.X11-unix 1777 root root 10d # Unlink the X11 lock files r! /tmp/.X[0-9]*-lock
The second line in contrast to the first one would break a
running system, and will only be executed with
--boot.
Note that for all line types that result in creation of any kind of file node
(i.e. f/F,
d/D/v/q/Q,
p, L, c/b and C)
leading directories are implicitly created if needed, owned by root with an access mode of 0755. In order to
create them with different modes or ownership make sure to add appropriate d lines.
The file system path specification supports simple specifier expansion, see below. The path (after expansion) must be absolute.
The file access mode to use when creating this file or
directory. If omitted or when set to "-", the
default is used: 0755 for directories, 0644 for all other file
objects. For z, Z lines,
if omitted or when set to "-", the file access
mode will not be modified. This parameter is ignored for
x, r,
R, L, t,
and a lines.
Optionally, if prefixed with "~", the
access mode is masked based on the already set access bits for
existing file or directories: if the existing file has all
executable bits unset, all executable bits are removed from the
new access mode, too. Similarly, if all read bits are removed
from the old access mode, they will be removed from the new
access mode too, and if all write bits are removed, they will be
removed from the new access mode too. In addition, the
sticky/SUID/SGID bit is removed unless applied to a
directory. This functionality is particularly useful in
conjunction with Z.
The user and group to use for this file or directory. This
may either be a numeric user/group ID or a user or group
name. If omitted or when set to "-", the
default 0 (root) is used. For z and
Z lines, when omitted or when set to
"-", the file ownership will not be
modified. These parameters are ignored for x,
r, R,
L, t, and
a lines.
The date field, when set, is used to decide what files to
delete when cleaning. If a file or directory is older than the
current time minus the age field, it is deleted. The field
format is a series of integers each followed by one of the
following suffixes for the respective time units:
s,
m or min,
h,
d,
w,
ms, and
us,
meaning seconds, minutes, hours, days, weeks,
milliseconds, and microseconds, respectively. Full names of the time units can
be used too.
If multiple integers and units are specified, the time
values are summed. If an integer is given without a unit,
s is assumed.
When the age is set to zero, the files are cleaned unconditionally.
The age field only applies to lines starting with
d, D, e,
v, q,
Q, C, x
and X. If omitted or set to
"-", no automatic clean-up is done.
If the age field starts with a tilde character
"~", the clean-up is only applied to files and
directories one level inside the directory specified, but not
the files and directories immediately inside it.
The age of a file system entry is determined from its last modification timestamp (mtime), its last access timestamp (atime), and (except for directories) its last status change timestamp (ctime). Any of these three (or two) values will prevent cleanup if it is more recent than the current time minus the age field.
For L lines determines the destination path of the symlink. For c and
b, determines the major/minor of the device node, with major and minor formatted as integers,
separated by ":", e.g. "1:3". For f, F,
and w, the argument may be used to specify a short string that is written to the file,
suffixed by a newline. For C, specifies the source file or directory. For t
and T, determines extended attributes to be set. For a and
A, determines ACL attributes to be set. For h and H,
determines the file attributes to set. Ignored for all other lines.
This field can contain specifiers, see below.
Specifiers can be used in the "path" and "argument" fields. An unknown or unresolvable specifier is treated as invalid configuration. The following expansions are understood:
Table 1. Specifiers available
| Specifier | Meaning | Details |
|---|---|---|
"%b" | Boot ID | The boot ID of the running system, formatted as string. See random(4) for more information. |
"%C" | System or user cache directory | In --user mode, this is the same as $XDG_CACHE_HOME, and /var/cache otherwise. |
"%h" | User home directory | This is the home directory of the user running the command. In case of the system instance this resolves to "/root". |
"%H" | Host name | The hostname of the running system. |
"%L" | System or user log directory | In --user mode, this is the same as $XDG_CONFIG_HOME with /log appended, and /var/log otherwise. |
"%m" | Machine ID | The machine ID of the running system, formatted as string. See machine-id(5) for more information. |
"%S" | System or user state directory | In --user mode, this is the same as $XDG_CONFIG_HOME, and /var/lib otherwise. |
"%t" | System or user runtime directory | In --user mode, this is the same $XDG_RUNTIME_DIR, and /run otherwise. |
"%T" | Directory for temporary files | This is either /tmp or the path "$TMPDIR", "$TEMP" or "$TMP" are set to. |
"%u" | User name | This is the name of the user running the command. In case of the system instance this resolves to "root". |
"%U" | User UID | This is the numeric UID of the user running the command. In case of the system instance this resolves to 0. |
"%v" | Kernel release | Identical to uname -r output. |
"%V" | Directory for larger and persistent temporary files | This is either /var/tmp or the path "$TMPDIR", "$TEMP" or "$TMP" are set to. |
"%%" | Escaped "%" | Single percent sign. |
Example 1. Create directories with specific mode and ownership
screen(1), needs two directories created at boot with specific modes and ownership:
# /usr/lib/tmpfiles.d/screen.conf d /run/screens 1777 root screen 10d d /run/uscreens 0755 root screen 10d12h
Contents of /run/screens and /run/uscreens will
be cleaned up after 10 and 10½ days, respectively.
Example 2. Create a directory with a SMACK attribute
D /run/cups - - - -
t /run/cups - - - - security.SMACK64=printing user.attr-with-spaces="foo bar"
The directory will be owned by root and have default mode. Its contents are not subject to time based cleanup, but will be obliterated when systemd-tmpfiles --remove runs.
Example 3. Create a directory and prevent its contents from cleanup
abrt(1),
needs a directory created at boot with specific mode and ownership and its content
should be preserved from the automatic cleanup applied to the contents of
/var/tmp:
# /usr/lib/tmpfiles.d/tmp.conf d /var/tmp 1777 root root 30d
# /usr/lib/tmpfiles.d/abrt.conf d /var/tmp/abrt 0755 abrt abrt -
Example 4. Apply clean up during boot and based on time
# /usr/lib/tmpfiles.d/dnf.conf r! /var/cache/dnf/*/*/download_lock.pid r! /var/cache/dnf/*/*/metadata_lock.pid r! /var/lib/dnf/rpmdb_lock.pid e /var/cache/dnf/ - - - 30d
The lock files will be removed during boot. Any files and directories in
/var/cache/dnf/ will be removed after they have not been
accessed in 30 days.
Example 5. Empty the contents of a cache directory on boot
# /usr/lib/tmpfiles.d/krb5rcache.conf e! /var/cache/krb5rcache - - - 0
Any files and subdirectories in /var/cache/krb5rcache/
will be removed on boot. The directory will not be created.