systemd-tmpfiles(8) - Man pages

SYSTEMD-TMPFILES(8) systemd-tmpfiles SYSTEMD-TMPFILES(8)

NAME
systemd-tmpfiles, systemd-tmpfiles-setup.service, systemd-tmpfiles-
setup-dev-early.service, systemd-tmpfiles-setup-dev.service, systemd-
tmpfiles-clean.service, systemd-tmpfiles-clean.timer - Create, delete,
and clean up files and directories

SYNOPSIS

systemd-tmpfiles [OPTIONS...] [CONFIGFILE...]

System units:
systemd-tmpfiles-setup.service
systemd-tmpfiles-setup-dev-early.service
systemd-tmpfiles-setup-dev.service
systemd-tmpfiles-clean.service
systemd-tmpfiles-clean.timer

User units:
systemd-tmpfiles-setup.service
systemd-tmpfiles-clean.service
systemd-tmpfiles-clean.timer

DESCRIPTION
systemd-tmpfiles creates, deletes, and cleans up files and directories,
using the configuration file format and location specified in
tmpfiles.d(5). Historically, it was designed to manage volatile and
temporary files, as the name suggests, but it provides generic file
management functionality and can be used to manage any kind of files. It
must be invoked with one or more commands --create, --remove, and
--clean, to select the respective subset of operations.

If invoked with no arguments, directives from the configuration files
found in the directories specified by tmpfiles.d(5) are executed. When
invoked with positional arguments, if option --replace=PATH is
specified, arguments specified on the command line are used instead of
the configuration file PATH. Otherwise, just the configuration specified
by the command line arguments is executed. If the string "-" is
specified instead of a filename, the configuration is read from standard
input. If the argument is a file name (without any slashes), all
configuration directories are searched for a matching file and the file
found that has the highest priority is executed. If the argument is a
path, that file is used directly without searching the configuration
directories for any other matching file.

System services (systemd-tmpfiles-setup.service,
systemd-tmpfiles-setup-dev-early.service,
systemd-tmpfiles-setup-dev.service, systemd-tmpfiles-clean.service)
invoke systemd-tmpfiles to create system files and to perform system
wide cleanup. Those services read administrator-controlled configuration
files in tmpfiles.d/ directories. User services
(systemd-tmpfiles-setup.service, systemd-tmpfiles-clean.service) also
invoke systemd-tmpfiles, but it reads a separate set of files, which
includes user-controlled files under ~/.config/user-tmpfiles.d/ and
~/.local/share/user-tmpfiles.d/, and administrator-controlled files
under /usr/share/user-tmpfiles.d/. Users may use this to create and
clean up files under their control, but the system instance performs
global cleanup and is not influenced by user configuration. Note that
this means a time-based cleanup configured in the system instance, such
as the one typically configured for /tmp/, will thus also affect files
created by the user instance if they are placed in /tmp/, even if the
user instance's time-based cleanup is turned off.

To re-apply settings after configuration has been modified, simply
restart systemd-tmpfiles-clean.service, which will apply any settings
which can be safely executed at runtime. To debug systemd-tmpfiles, it
may be useful to invoke it directly from the command line with increased
log level (see $SYSTEMD_LOG_LEVEL below).

COMMANDS AND OPTIONS
The following commands are understood:

--create
If this command is passed, all files and directories marked with f,
F, w, d, D, v, p, L, c, b, m in the configuration files are created
or written to. Files and directories marked with z, Z, t, T, a, and
A have their ownership, access mode and security labels set.

--clean
If this command is passed, all files and directories with an age
parameter configured will be cleaned up.

--remove
If this command is passed, the contents of directories marked with D
or R, and files or directories themselves marked with r or R are
removed unless an exclusive or shared BSD lock is taken on them (see
flock(2)).

--purge
If this option is passed, all files and directories declared for
creation and marked with the "$" character by the tmpfiles.d/ files
specified on the command line will be deleted. Specifically, this
acts on all files and directories marked with f, F, d, D, v, q, Q,
p, L, c, b, C, w, e. If this switch is used at least one tmpfiles.d/
file (or - for standard input) must be specified on the command line
or the invocation will be refused, for safety reasons (as otherwise
much of the installed system files might be removed).

The primary usecase for this option is to automatically remove files
and directories that originally have been created on behalf of an
installed package at package removal time.

It is recommended to first run this command in combination with
--dry-run (see below) to verify which files and directories will be
deleted.

Warning! This is usually not the command you want! In most cases
--remove is what you are looking for.

Added in version 256.

--user
Execute "user" configuration, i.e. tmpfiles.d/ files in user
configuration directories.

Added in version 236.

--boot
Also execute lines with an exclamation mark. Lines that are not safe
to be executed on a running system may be marked in this way.
systemd-tmpfiles is executed in early boot with --boot specified and
will execute those lines. When invoked again later, it should be
called without --boot.

Added in version 209.

--graceful
Ignore configuration lines pertaining to unknown users or groups.
This option is intended to be used in early boot before all users or
groups have been created.

Added in version 254.

--dry-run
Process the configuration and print what operations would be
performed, but do not actually change anything in the file system.

Added in version 256.

--prefix=path
Only apply rules with paths that start with the specified prefix.
This option can be specified multiple times.

Added in version 212.

--exclude-prefix=path
Ignore rules with paths that start with the specified prefix. This
option can be specified multiple times.

Added in version 207.

-E
A shortcut for "--exclude-prefix=/dev --exclude-prefix=/proc
--exclude-prefix=/run --exclude-prefix=/sys", i.e. exclude the
hierarchies typically backed by virtual or memory file systems. This
is useful in combination with --root=, if the specified directory
tree contains an OS tree without these virtual/memory file systems
mounted in, as it is typically not desirable to create any files and
directories below these subdirectories if they are supposed to be
overmounted during runtime.

Added in version 247.

--root=root
Takes a directory path as an argument. All paths will be prefixed
with the given alternate root path, including config search paths.

When this option is used, the libc Name Service Switch (NSS) is
bypassed for resolving users and groups. Instead the files
/etc/passwd and /etc/group inside the alternate root are read
directly. This means that users/groups not listed in these files
will not be resolved, i.e. LDAP NIS and other complex databases are
not considered.

Consider combining this with -E to ensure the invocation does not
create files or directories below mount points in the OS image
operated on that are typically overmounted during runtime.

Added in version 212.

--image=image
Takes a path to a disk image file or block device node. If specified
all operations are applied to file system in the indicated disk
image. This is similar to --root= but operates on file systems
stored in disk images or block devices. The disk image should either
contain just a file system or a set of file systems within a GPT
partition table, following the Discoverable Partitions
Specification[1]. For further information on supported disk images,
see systemd-nspawn(1)'s switch of the same name.

Implies -E.

Added in version 247.

--image-policy=policy
Takes an image policy string as argument, as per systemd.image-
policy(7). The policy is enforced when operating on the disk image
specified via --image=, see above. If not specified, defaults to the
"*" policy, i.e. all recognized file systems in the image are used.

--replace=PATH
When this option is given, one or more positional arguments must be
specified. All configuration files found in the directories listed
in tmpfiles.d(5) will be read, and the configuration given on the
command line will be handled instead of and with the same priority
as the configuration file PATH.

This option is intended to be used when package installation scripts
are running and files belonging to that package are not yet
available on disk, so their contents must be given on the command
line, but the admin configuration might already exist and should be
given higher priority.

Added in version 238.

--cat-config
Copy the contents of config files to standard output. Before each
file, the filename is printed as a comment.

--tldr
Copy the contents of config files to standard output. Only the
"interesting" parts of the configuration files are printed, comments
and empty lines are skipped. Before each file, the filename is
printed as a comment.

--no-pager
Do not pipe output into a pager.

-h, --help
Print a short help text and exit.

--version
Print a short version string and exit.

It is possible to combine --create, --clean, and --remove in one
invocation (in which case removal and cleanup are executed before
creation of new files). For example, during boot the following command
line is executed to ensure that all temporary and volatile directories
are removed and created according to the configuration file:

systemd-tmpfiles --remove --create

CREDENTIALS
systemd-tmpfiles supports the service credentials logic as implemented
by ImportCredential=/LoadCredential=/SetCredential= (see systemd.exec(5)
for details). The following credentials are used when passed in:

tmpfiles.extra
The contents of this credential may contain additional lines to
operate on. The credential contents should follow the same format as
any other tmpfiles.d/ drop-in configuration file. If this credential
is passed it is processed after all of the drop-in files read from
the file system. The lines in the credential can hence augment
existing lines of the OS, but not override them.

Added in version 252.

Note that by default the systemd-tmpfiles-setup.service unit file (and
related unit files) is set up to inherit the "tmpfiles.extra" credential
from the service manager.

ENVIRONMENT
$SYSTEMD_LOG_LEVEL
The maximum log level of emitted messages (messages with a higher
log level, i.e. less important ones, will be suppressed). Takes a
comma-separated list of values. A value may be either one of (in
order of decreasing importance) emerg, alert, crit, err, warning,
notice, info, debug, or an integer in the range 0...7. See syslog(3)
for more information. Each value may optionally be prefixed with one
of console, syslog, kmsg or journal followed by a colon to set the
maximum log level for that specific log target (e.g.
SYSTEMD_LOG_LEVEL=debug,console:info specifies to log at debug level
except when logging to the console which should be at info level).
Note that the global maximum log level takes priority over any per
target maximum log levels.

$SYSTEMD_LOG_COLOR
A boolean. If true, messages written to the tty will be colored
according to priority.

This setting is only useful when messages are written directly to
the terminal, because journalctl(1) and other tools that display
logs will color messages based on the log level on their own.

$SYSTEMD_LOG_TIME
A boolean. If true, console log messages will be prefixed with a
timestamp.

This setting is only useful when messages are written directly to
the terminal or a file, because journalctl(1) and other tools that
display logs will attach timestamps based on the entry metadata on
their own.

$SYSTEMD_LOG_LOCATION
A boolean. If true, messages will be prefixed with a filename and
line number in the source code where the message originates.

Note that the log location is often attached as metadata to journal
entries anyway. Including it directly in the message text can
nevertheless be convenient when debugging programs.

$SYSTEMD_LOG_TARGET
The destination for log messages. One of console (log to the
attached tty), console-prefixed (log to the attached tty but with
prefixes encoding the log level and "facility", see syslog(3), kmsg
(log to the kernel circular log buffer), journal (log to the
journal), journal-or-kmsg (log to the journal if available, and to
kmsg otherwise), auto (determine the appropriate log target
automatically, the default), null (disable log output).

$SYSTEMD_PAGER, $PAGER
Pager to use when --no-pager is not given. $SYSTEMD_PAGER is used
if set; otherwise $PAGER is used. If neither $SYSTEMD_PAGER nor
$PAGER are set, a set of well-known pager implementations is tried
in turn, including less(1) and more(1), until one is found. If no
pager implementation is discovered, no pager is invoked. Setting
those environment variables to an empty string or the value "cat" is
equivalent to passing --no-pager.

Note: if $SYSTEMD_PAGERSECURE is not set, $SYSTEMD_PAGER and $PAGER
can only be used to disable the pager (with "cat" or ""), and are
otherwise ignored.

$SYSTEMD_LESS
Override the options passed to less (by default "FRSXMK").

Users might want to change two options in particular:

K
This option instructs the pager to exit immediately when Ctrl+C
is pressed. To allow less to handle Ctrl+C itself to switch back
to the pager command prompt, unset this option.

If the value of $SYSTEMD_LESS does not include "K", and the
pager that is invoked is less, Ctrl+C will be ignored by the
executable, and needs to be handled by the pager.

X
This option instructs the pager to not send termcap
initialization and deinitialization strings to the terminal. It
is set by default to allow command output to remain visible in
the terminal even after the pager exits. Nevertheless, this
prevents some pager functionality from working, in particular
paged output cannot be scrolled with the mouse.

Note that setting the regular $LESS environment variable has no
effect for less invocations by systemd tools.

See less(1) for more discussion.

$SYSTEMD_LESSCHARSET
Override the charset passed to less (by default "utf-8", if the
invoking terminal is determined to be UTF-8 compatible).

Note that setting the regular $LESSCHARSET environment variable has
no effect for less invocations by systemd tools.

$SYSTEMD_PAGERSECURE
Common pager commands like less(1), in addition to "paging", i.e.
scrolling through the output, support opening of or writing to other
files and running arbitrary shell commands. When commands are
invoked with elevated privileges, for example under sudo(8) or
pkexec(1), the pager becomes a security boundary. Care must be taken
that only programs with strictly limited functionality are used as
pagers, and unintended interactive features like opening or creation
of new files or starting of subprocesses are not allowed. "Secure
mode" for the pager may be enabled as described below, if the pager
supports that (most pagers are not written in a way that takes this
into consideration). It is recommended to either explicitly enable
"secure mode" or to completely disable the pager using --no-pager or
PAGER=cat when allowing untrusted users to execute commands with
elevated privileges.

This option takes a boolean argument. When set to true, the "secure
mode" of the pager is enabled. In "secure mode", LESSSECURE=1 will
be set when invoking the pager, which instructs the pager to disable
commands that open or create new files or start new subprocesses.
Currently only less(1) is known to understand this variable and
implement "secure mode".

When set to false, no limitation is placed on the pager. Setting
SYSTEMD_PAGERSECURE=0 or not removing it from the inherited
environment may allow the user to invoke arbitrary commands.

When $SYSTEMD_PAGERSECURE is not set, systemd tools attempt to
automatically figure out if "secure mode" should be enabled and
whether the pager supports it. "Secure mode" is enabled if the
effective UID is not the same as the owner of the login session, see
geteuid(2) and sd_pid_get_owner_uid(3), or when running under
sudo(8) or similar tools ($SUDO_UID is set [2]). In those cases,
SYSTEMD_PAGERSECURE=1 will be set and pagers which are not known to
implement "secure mode" will not be used at all. Note that this
autodetection only covers the most common mechanisms to elevate
privileges and is intended as convenience. It is recommended to
explicitly set $SYSTEMD_PAGERSECURE or disable the pager.

Note that if the $SYSTEMD_PAGER or $PAGER variables are to be
honoured, other than to disable the pager, $SYSTEMD_PAGERSECURE must
be set too.

$SYSTEMD_COLORS
Takes a boolean argument. When true, systemd and related utilities
will use colors in their output, otherwise the output will be
monochrome. Additionally, the variable can take one of the following
special values: "16", "256" to restrict the use of colors to the
base 16 or 256 ANSI colors, respectively. This can be specified to
override the automatic decision based on $TERM and what the console
is connected to.

$SYSTEMD_URLIFY
The value must be a boolean. Controls whether clickable links should
be generated in the output for terminal emulators supporting this.
This can be specified to override the decision that systemd makes
based on $TERM and other conditions.

UNPRIVILEGED --CLEANUP OPERATION
systemd-tmpfiles tries to avoid changing the access and modification
times on the directories it accesses, which requires CAP_FOWNER
privileges. When running as non-root, directories which are checked for
files to clean up will have their access time bumped, which might
prevent their cleanup.

EXIT STATUS
On success, 0 is returned. If the configuration was syntactically
invalid (syntax errors, missing arguments, ...), so some lines had to be
ignored, but no other errors occurred, 65 is returned (EX_DATAERR from
/usr/include/sysexits.h). If the configuration was syntactically valid,
but could not be executed (lack of permissions, creation of files in
missing directories, invalid contents when writing to /sys/ values,
...), 73 is returned (EX_CANTCREAT from /usr/include/sysexits.h).
Otherwise, 1 is returned (EXIT_FAILURE from /usr/include/stdlib.h).

Note: when creating items, if the target already exists, but is of the
wrong type or otherwise does not match the requested state, and forced
operation has not been requested with "+", a message is emitted, but the
failure is otherwise ignored.