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.

SEE ALSO

systemd(1), tmpfiles.d(5)

NOTES

1.  Discoverable Partitions Specification
    https://uapi-group.org/specifications/specs/discoverable_partitions_specification

2.  It is recommended for other tools to set and check $SUDO_UID as appropriate, treating it is a common interface.