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
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. 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/nullThe 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, it will be written to the file.
F¶Create or truncate a file. If the argument parameter is given, it will be written to the file.
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.
d¶Create a directory if it does not exist yet.
D¶Create or empty a directory.
v¶Create a subvolume if the path does not
exist yet and the file system supports this
(btrfs). Otherwise create a normal directory, in the same
way as d.
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
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.
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.
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.
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.
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.
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.
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.
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.
a, a+¶Set POSIX ACLs (access control lists). If
suffixed with +, 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 explictly 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.
A, A+¶Same as a and
a+, but recursive.
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.
The file system path specification supports simple specifier expansion. The following expansions are understood:
Table 1. Specifiers available
| Specifier | Meaning | Details |
|---|---|---|
"%m" | Machine ID | The machine ID of the running system, formatted as string. See machine-id(5) for more information. |
"%b" | Boot ID | The boot ID of the running system, formatted as string. See random(4) for more information. |
"%H" | Host name | The hostname of the running system. |
"%v" | Kernel release | Identical to uname -r output. |
"%%" | Escaped % | Single percent sign. |
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,
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 postfixes for the respective time units:
s, min, h, d, w, ms, m, us¶If multiple integers and units are specified, the time
values are summed up. 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, 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.
For L lines determines the destination
path of the symlink. For c,
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 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 determines extended
attributes to be set. For a determines
ACL attributes to be set. Ignored for all other lines.
Example 1. /etc/tmpfiles.d/screen.conf example
screen needs two directories created at boot with specific modes and ownership.
d /run/screens 1777 root root 10d
d /run/uscreens 0755 root root 10d12h
t /run/screen - - - - user.name="John Smith" security.SMACK64=screenExample 2. /etc/tmpfiles.d/abrt.conf example
abrt needs a directory created at boot with specific mode and ownership and its content should be preserved.
d /var/tmp/abrt 0755 abrt abrt
x /var/tmp/abrt/*