# systemd-system.conf

## NAME



           systemd-system.conf, system.conf.d, systemd-user.conf, user.conf.d
           - System and session service manager configuration files
    


## SYNOPSIS



           /etc/systemd/system.conf, /run/systemd/system.conf,
           /usr/lib/systemd/system.conf, /etc/systemd/system.conf.d/*.conf,
           /run/systemd/system.conf.d/*.conf,
           /usr/lib/systemd/system.conf.d/*.conf
    
           ~/.config/systemd/user.conf, /etc/systemd/user.conf,
           /run/systemd/user.conf, /usr/lib/systemd/user.conf,
           /etc/systemd/user.conf.d/*.conf, /run/systemd/user.conf.d/*.conf,
           /usr/lib/systemd/user.conf.d/*.conf
    


## DESCRIPTION



           When run as a system instance, **systemd** interprets the
           configuration file system.conf and the files in system.conf.d
           directories; when run as a user instance, it interprets the
           configuration file user.conf (in order of priority, in the home
           directory of the user and under /etc/systemd/, /run/systemd/, and
           /usr/lib/systemd/) and the files in user.conf.d directories. These
           configuration files contain a few settings controlling basic
           manager operations.
    
           See systemd.syntax(7) for a general description of the syntax.
    


## CONFIGURATION DIRECTORIES AND PRECEDENCE



           The default configuration is set during compilation, so
           configuration is only needed when it is necessary to deviate from
           those defaults. The main configuration file is loaded from one of
           the listed directories in order of priority, only the first file
           found is used: /etc/systemd/, /run/systemd/,
           /usr/local/lib/systemd/ [1], /usr/lib/systemd/. The vendor version
           of the file contains commented out entries showing the defaults as
           a guide to the administrator. Local overrides can also be created
           by creating drop-ins, as described below. The main configuration
           file can also be edited for this purpose (or a copy in /etc/ if it
           is shipped under /usr/), however using drop-ins for local
           configuration is recommended over modifications to the main
           configuration file.
    
           In addition to the main configuration file, drop-in configuration
           snippets are read from /usr/lib/systemd/*.conf.d/,
           /usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/.
           Those drop-ins have higher precedence and override the main
           configuration file. Files in the *.conf.d/ configuration
           subdirectories are sorted by their filename in lexicographic
           order, regardless of in which of the subdirectories they reside.
           When multiple files specify the same option, for options which
           accept just a single value, the entry in the file sorted last
           takes precedence, and for options which accept a list of values,
           entries are collected as they occur in the sorted files.
    
           When packages need to customize the configuration, they can
           install drop-ins under /usr/. Files in /etc/ are reserved for the
           local administrator, who may use this logic to override the
           configuration files installed by vendor packages. Drop-ins have to
           be used to override package drop-ins, since the main configuration
           file has lower precedence. It is recommended to prefix all
           filenames in those subdirectories with a two-digit number and a
           dash, to simplify the ordering. This also defines a concept of
           drop-in priorities to allow OS vendors to ship drop-ins within a
           specific range lower than the range used by users. This should
           lower the risk of package drop-ins overriding accidentally
           drop-ins defined by users. It is recommended to use the range
           10-40 for drop-ins in /usr/ and the range 60-90 for drop-ins in
           /etc/ and /run/, to make sure that local and transient drop-ins
           take priority over drop-ins shipped by the OS vendor.
    
           To disable a configuration file supplied by the vendor, the
           recommended way is to place a symlink to /dev/null in the
           configuration directory in /etc/, with the same filename as the
           vendor configuration file.
    


## OPTIONS



           All options are configured in the [Manager] section:
    
           _LogColor=_ , _LogLevel=_ , _LogLocation=_ , _LogTarget=_ , _LogTime=_ ,
           _DumpCore=yes_ , _CrashChangeVT=no_ , _CrashShell=no_ , _CrashAction=freeze_ ,
           _ShowStatus=yes_ , _DefaultStandardOutput=journal_ ,
           _DefaultStandardError=inherit_
               Configures various parameters of basic manager operation.
               These options may be overridden by the respective process and
               kernel command line arguments. See systemd(1) for details.
    
               Added in version 198.
    
           _CtrlAltDelBurstAction=_
               Defines what action will be performed if user presses
               Ctrl-Alt-Delete more than 7 times in 2s. Can be set to
               "reboot-force", "poweroff-force", "reboot-immediate",
               "poweroff-immediate" or disabled with "none". Defaults to
               "reboot-force".
    
               Added in version 232.
    
           _StatusUnitFormat=_
               Takes **name** , **description** or **combined** as the value. If **name** , the
               system manager will use unit names in status messages (e.g.
               "systemd-journald.service"), instead of the longer and more
               informative descriptions set with _Description=_ (e.g.  "Journal
               Logging Service"). If **combined** , the system manager will use
               both unit names and descriptions in status messages (e.g.
               "systemd-journald.service - Journal Logging Service").
    
               See systemd.unit(5) for details about unit names and
               _Description=_.
    
               Added in version 243.
    
           _DefaultTimerAccuracySec=_
               Sets the default accuracy of timer units. This controls the
               global default for the _AccuracySec=_ setting of timer units,
               see systemd.timer(5) for details.  _AccuracySec=_ set in
               individual units override the global default for the specific
               unit. Defaults to 1min. Note that the accuracy of timer units
               is also affected by the configured timer slack for PID 1, see
               _TimerSlackNSec=_ above.
    
               Added in version 212.
    


## RESOURCE MANAGEMENT



           _TimerSlackNSec=_
               Sets the timer slack in nanoseconds for PID 1, which is
               inherited by all executed processes, unless overridden
               individually, for example with the _TimerSlackNSec=_ setting in
               service units (for details see systemd.exec(5)). The timer
               slack controls the accuracy of wake-ups triggered by system
               timers. See prctl(2) for more information. Note that in
               contrast to most other time span definitions this parameter
               takes an integer value in nano-seconds if no unit is
               specified. The usual time units are understood too.
    
               Added in version 198.
    
           _CPUAffinity=_
               Configures the CPU affinity for the service manager as well as
               the default CPU affinity for all forked off processes. Takes a
               list of CPU indices or ranges separated by either whitespace
               or commas. CPU ranges are specified by the lower and upper CPU
               indices separated by a dash. This option may be specified more
               than once, in which case the specified CPU affinity masks are
               merged. If the empty string is assigned, the mask is reset,
               all assignments prior to this will have no effect. Individual
               services may override the CPU affinity for their processes
               with the _CPUAffinity=_ setting in unit files, see
               systemd.exec(5).
    
               Added in version 198.
    
           _NUMAPolicy=_
               Configures the NUMA memory policy for the service manager and
               the default NUMA memory policy for all forked off processes.
               Individual services may override the default policy with the
               _NUMAPolicy=_ setting in unit files, see systemd.exec(5).
    
               Added in version 243.
    
           _NUMAMask=_
               Configures the NUMA node mask that will be associated with the
               selected NUMA policy. Note that **default** and **local** NUMA
               policies do not require explicit NUMA node mask and value of
               the option can be empty. Similarly to _NUMAPolicy=_ , value can
               be overridden by individual services in unit files, see
               systemd.exec(5).
    
               Added in version 243.
    
           _DefaultMemoryAccounting=_ , _DefaultTasksAccounting=_ ,
           _DefaultIOAccounting=_ , _DefaultIPAccounting=_
               Configure the default resource accounting settings, as
               configured per-unit by _MemoryAccounting=_ , _TasksAccounting=_ ,
               _IOAccounting=_ , and _IPAccounting=_. See
               systemd.resource-control(5) for details on the per-unit
               settings.
    
               _DefaultMemoryAccounting=_ defaults to yes.
               _DefaultTasksAccounting=_ defaults to yes. The other settings
               default to no.
    
               Added in version 211.
    
           _DefaultTasksMax=_
               Configure the default value for the per-unit _TasksMax=_
               setting. See systemd.resource-control(5) for details. This
               setting applies to all unit types that support resource
               control settings, with the exception of slice units. Defaults
               to 15% of the minimum of _kernel.pid_max=_ , _kernel.threads-max=_
               and root cgroup _pids.max_. Kernel has a default value for
               _kernel.pid_max=_ and an algorithm of counting in case of more
               than 32 cores. For example, with the default _kernel.pid_max=_ ,
               _DefaultTasksMax=_ defaults to 4915, but might be greater in
               other systems or smaller in OS containers.
    
               Added in version 228.
    
           _DefaultLimitCPU=_ , _DefaultLimitFSIZE=_ , _DefaultLimitDATA=_ ,
           _DefaultLimitSTACK=_ , _DefaultLimitCORE=_ , _DefaultLimitRSS=_ ,
           _DefaultLimitNOFILE=_ , _DefaultLimitAS=_ , _DefaultLimitNPROC=_ ,
           _DefaultLimitMEMLOCK=_ , _DefaultLimitLOCKS=_ , _DefaultLimitSIGPENDING=_ ,
           _DefaultLimitMSGQUEUE=_ , _DefaultLimitNICE=_ , _DefaultLimitRTPRIO=_ ,
           _DefaultLimitRTTIME=_
               These settings control various default resource limits for
               processes executed by units. See setrlimit(2) for details.
               These settings may be overridden in individual units using the
               corresponding _LimitXXX=_ directives and they accept the same
               parameter syntax, see systemd.exec(5) for details. Note that
               these resource limits are only defaults for units, they are
               not applied to the service manager process (i.e. PID 1)
               itself.
    
               Most of these settings are unset, which means the resource
               limits are inherited from the kernel or, if invoked in a
               container, from the container manager. However, the following
               have defaults:
    
               •   _DefaultLimitNOFILE=_ defaults to 1024:524288.
    
               •   _DefaultLimitMEMLOCK=_ defaults to 8M.
    
               •   _DefaultLimitCORE=_ does not have a default but it is worth
                   mentioning that _RLIMIT_CORE_ is set to "infinity" by PID 1
                   which is inherited by its children.
    
               Note that the service manager internally in PID 1 bumps
               _RLIMIT_NOFILE_ and _RLIMIT_MEMLOCK_ to higher values, however the
               limit is reverted to the mentioned defaults for all child
               processes forked off.
    
               Added in version 198.
    
           _DefaultOOMPolicy=_
               Configure the default policy for reacting to processes being
               killed by the Linux Out-Of-Memory (OOM) killer or
               **systemd-oomd**. This may be used to pick a global default for
               the per-unit _OOMPolicy=_ setting. See systemd.service(5) for
               details. Note that this default is not used for services that
               have _Delegate=_ turned on.
    
               Added in version 243.
    
           _DefaultOOMScoreAdjust=_
               Configures the default OOM score adjustments of processes run
               by the service manager. This defaults to unset (meaning the
               forked off processes inherit the service manager's OOM score
               adjustment value), except if the service manager is run for an
               unprivileged user, in which case this defaults to the service
               manager's OOM adjustment value plus 100 (this makes service
               processes slightly more likely to be killed under memory
               pressure than the manager itself). This may be used to pick a
               global default for the per-unit _OOMScoreAdjust=_ setting. See
               systemd.exec(5) for details. Note that this setting has no
               effect on the OOM score adjustment value of the service
               manager process itself, it retains the original value set
               during its invocation.
    
               Added in version 250.
    
           _DefaultMemoryPressureWatch=_ , _DefaultMemoryPressureThresholdSec=_
               Configures the default settings for the per-unit
               _MemoryPressureWatch=_ and _MemoryPressureThresholdSec=_ settings.
               See systemd.resource-control(5) for details. Defaults to
               "auto" and "200ms", respectively. This also sets the memory
               pressure monitoring threshold for the service manager itself.
    
               Added in version 254.
    


## HARDWARE WATCHDOG



           _RuntimeWatchdogSec=_ , _RebootWatchdogSec=_ , _KExecWatchdogSec=_
               Configure the hardware watchdog at runtime and at reboot.
               Takes a timeout value in seconds (or in other time units if
               suffixed with "ms", "min", "h", "d", "w"), or the special
               strings "off" or "default". If set to "off" (alternatively:
               "0") the watchdog logic is disabled: no watchdog device is
               opened, configured, or pinged. If set to the special string
               "default" the watchdog is opened and pinged in regular
               intervals, but the timeout is not changed from the default. If
               set to any other time value the watchdog timeout is configured
               to the specified value (or a value close to it, depending on
               hardware capabilities).
    
               If _RuntimeWatchdogSec=_ is set to a non-zero value, the
               watchdog hardware (/dev/watchdog0 or the path specified with
               _WatchdogDevice=_ or the kernel option _systemd.watchdog_device=_)
               will be programmed to automatically reboot the system if it is
               not contacted within the specified timeout interval. The
               system manager will ensure to contact it at least once in half
               the specified timeout interval. This feature requires a
               hardware watchdog device to be present, as it is commonly the
               case in embedded and server systems. Not all hardware
               watchdogs allow configuration of all possible reboot timeout
               values, in which case the closest available timeout is picked.
    
               _RebootWatchdogSec=_ may be used to configure the hardware
               watchdog when the system is asked to reboot. It works as a
               safety net to ensure that the reboot takes place even if a
               clean reboot attempt times out. Note that the
               _RebootWatchdogSec=_ timeout applies only to the second phase of
               the reboot, i.e. after all regular services are already
               terminated, and after the system and service manager process
               (PID 1) got replaced by the systemd-shutdown binary, see
               system bootup(7) for details. During the first phase of the
               shutdown operation the system and service manager remains
               running and hence _RuntimeWatchdogSec=_ is still honoured. In
               order to define a timeout on this first phase of system
               shutdown, configure _JobTimeoutSec=_ and _JobTimeoutAction=_ in
               the [Unit] section of the shutdown.target unit. By default,
               _RuntimeWatchdogSec=_ defaults to 0 (off), and
               _RebootWatchdogSec=_ to 10min.
    
               _KExecWatchdogSec=_ may be used to additionally enable the
               watchdog when kexec is being executed rather than when
               rebooting. Note that if the kernel does not reset the watchdog
               on kexec (depending on the specific hardware and/or driver),
               in this case the watchdog might not get disabled after kexec
               succeeds and thus the system might get rebooted, unless
               _RuntimeWatchdogSec=_ is also enabled at the same time. For this
               reason it is recommended to enable _KExecWatchdogSec=_ only if
               _RuntimeWatchdogSec=_ is also enabled.
    
               These settings have no effect if a hardware watchdog is not
               available.
    
               Added in version 198.
    
           _RuntimeWatchdogPreSec=_
               Configure the hardware watchdog device pre-timeout value.
               Takes a timeout value in seconds (or in other time units
               similar to _RuntimeWatchdogSec=_). A watchdog pre-timeout is a
               notification generated by the watchdog before the watchdog
               reset might occur in the event the watchdog has not been
               serviced. This notification is handled by the kernel and can
               be configured to take an action (i.e. generate a kernel panic)
               using _RuntimeWatchdogPreGovernor=_. Not all watchdog hardware
               or drivers support generating a pre-timeout and depending on
               the state of the system, the kernel may be unable to take the
               configured action before the watchdog reboot. The watchdog
               will be configured to generate the pre-timeout event at the
               amount of time specified by _RuntimeWatchdogPreSec=_ before the
               runtime watchdog timeout (set by _RuntimeWatchdogSec=_). For
               example, if the we have _RuntimeWatchdogSec=30_ and
               _RuntimeWatchdogPreSec=10_ , then the pre-timeout event will
               occur if the watchdog has not pinged for 20s (10s before the
               watchdog would fire). By default, _RuntimeWatchdogPreSec=_
               defaults to 0 (off). The value set for _RuntimeWatchdogPreSec=_
               must be smaller than the timeout value for
               _RuntimeWatchdogSec=_. This setting has no effect if a hardware
               watchdog is not available or the hardware watchdog does not
               support a pre-timeout and will be ignored by the kernel if the
               setting is greater than the actual watchdog timeout.
    
               Added in version 251.
    
           _RuntimeWatchdogPreGovernor=_
               Configure the action taken by the hardware watchdog device
               when the pre-timeout expires. The default action for the
               pre-timeout event depends on the kernel configuration, but it
               is usually to log a kernel message. For a list of valid
               actions available for a given watchdog device, check the
               content of the
               /sys/class/watchdog/watchdog _X_ /pretimeout_available_governors
               file. Typically, available governor types are _noop_ and _panic_.
               Availability, names and functionality might vary depending on
               the specific device driver in use. If the
               pretimeout_available_governors sysfs file is empty, the
               governor might be built as a kernel module and might need to
               be manually loaded (e.g.  _pretimeout_noop.ko_), or the watchdog
               device might not support pre-timeouts.
    
               Added in version 251.
    
           _WatchdogDevice=_
               Configure the hardware watchdog device that the runtime and
               shutdown watchdog timers will open and use. Defaults to
               /dev/watchdog0. This setting has no effect if a hardware
               watchdog is not available.
    
               Added in version 236.
    


## SECURITY



           _CapabilityBoundingSet=_
               Controls which capabilities to include in the capability
               bounding set for PID 1 and its children. See capabilities(7)
               for details. Takes a whitespace-separated list of capability
               names as read by cap_from_name(3). Capabilities listed will be
               included in the bounding set, all others are removed. If the
               list of capabilities is prefixed with ~, all but the listed
               capabilities will be included, the effect of the assignment
               inverted. Note that this option also affects the respective
               capabilities in the effective, permitted and inheritable
               capability sets. The capability bounding set may also be
               individually configured for units using the
               _CapabilityBoundingSet=_ directive for units, but note that
               capabilities dropped for PID 1 cannot be regained in
               individual units, they are lost for good.
    
               Added in version 198.
    
           _NoNewPrivileges=_
               Takes a boolean argument. If true, ensures that PID 1 and all
               its children can never gain new privileges through execve(2)
               (e.g. via setuid or setgid bits, or filesystem capabilities).
               Defaults to false. General purpose distributions commonly rely
               on executables with setuid or setgid bits and will thus not
               function properly with this option enabled. Individual units
               cannot disable this option. Also see **No New Privileges**
               **Flag******[2].
    
               Added in version 239._ProtectSystem=_
               Takes a boolean argument or the string "auto". If set to true
               this will remount /usr/ read-only. If set to "auto" (the
               default) and running in an initrd equivalent to true,
               otherwise false. This implements a restricted subset of the
               per-unit setting of the same name, see systemd.exec(5) for
               details: currently, the "full" or "strict" values are not
               supported.
    
               Added in version 256.
    
           _SystemCallArchitectures=_
               Takes a space-separated list of architecture identifiers.
               Selects from which architectures system calls may be invoked
               on this system. This may be used as an effective way to
               disable invocation of non-native binaries system-wide, for
               example to prohibit execution of 32-bit x86 binaries on 64-bit
               x86-64 systems. This option operates system-wide, and acts
               similar to the _SystemCallArchitectures=_ setting of unit files,
               see systemd.exec(5) for details. This setting defaults to the
               empty list, in which case no filtering of system calls based
               on architecture is applied. Known architecture identifiers are
               "x86", "x86-64", "x32", "arm" and the special identifier
               "native". The latter implicitly maps to the native
               architecture of the system (or more specifically, the
               architecture the system manager was compiled for). Set this
               setting to "native" to prohibit execution of any non-native
               binaries. When a binary executes a system call of an
               architecture that is not listed in this setting, it will be
               immediately terminated with the SIGSYS signal.
    
               Added in version 209.
    
           _DefaultSmackProcessLabel=_
               Takes a **SMACK64** security label as the argument. The process
               executed by a unit will be started under this label if
               _SmackProcessLabel=_ is not set in the unit. See systemd.exec(5)
               for the details.
    
               If the value is "/", only labels specified with
               _SmackProcessLabel=_ are assigned and the compile-time default
               is ignored.
    
               Added in version 252.
    
           _DefaultRestrictSUIDSGID=_
               Takes a boolean argument. This is used as a default for units
               which lack an explicit definition for _RestrictSUIDSGID=_. See
               systemd.exec(5) for the details.
    
               Added in version 258.
    


## TIMEOUTS AND RATE LIMITS



           _DefaultTimeoutStartSec=_ , _DefaultTimeoutStopSec=_ ,
           _DefaultTimeoutAbortSec=_ , _DefaultRestartSec=_
               Configures the default timeouts for starting, stopping and
               aborting of units, as well as the default time to sleep
               between automatic restarts of units, as configured per-unit in
               _TimeoutStartSec=_ , _TimeoutStopSec=_ , _TimeoutAbortSec=_ and
               _RestartSec=_ (for services, see systemd.service(5) for details
               on the per-unit settings). For non-service units,
               _DefaultTimeoutStartSec=_ sets the default _TimeoutSec=_ value.
    
               _DefaultTimeoutStartSec=_ and _DefaultTimeoutStopSec=_ default to
               90 s in the system manager and 90 s in the user manager.
               _DefaultTimeoutAbortSec=_ is not set by default so that all
               units fall back to _TimeoutStopSec=_.  _DefaultRestartSec=_
               defaults to 100 ms.
    
               Added in version 209.
    
           _DefaultDeviceTimeoutSec=_
               Configures the default timeout for waiting for devices. It can
               be changed per device via the _x-systemd.device-timeout=_ option
               in /etc/fstab and /etc/crypttab (see systemd.mount(5),
               crypttab(5)). Defaults to 90 s in the system manager and 90 s
               in the user manager.
    
               Added in version 252.
    
           _DefaultStartLimitIntervalSec=_ , _DefaultStartLimitBurst=_
               Configure the default unit start rate limiting, as configured
               per-service by _StartLimitIntervalSec=_ and _StartLimitBurst=_.
               See systemd.service(5) for details on the per-service
               settings.  _DefaultStartLimitIntervalSec=_ defaults to 10s.
               _DefaultStartLimitBurst=_ defaults to 5.
    
               Added in version 209.
    
           _ReloadLimitIntervalSec=_ , _ReloadLimitBurst=_
               Rate limiting for daemon-reload and (since v256) daemon-reexec
               requests. The setting applies to both operations, but the rate
               limits are tracked separately. Defaults to unset, and any
               number of operations can be requested at any time.
               _ReloadLimitIntervalSec=_ takes a value in seconds to configure
               the rate limit window, and _ReloadLimitBurst=_ takes a positive
               integer to configure the maximum allowed number of operations
               within the configured time window.
    
               Added in version 253.
    


## ENVIRONMENT



           _ManagerEnvironment=_
               Takes the same arguments as _DefaultEnvironment=_ , see above.
               Sets environment variables for the manager process itself.
               These variables are inherited by processes spawned by user
               managers, but not the system manager - use _DefaultEnvironment=_
               for that. Note that these variables are merged into the
               existing environment block. In particular, in case of the
               system manager, this includes variables set by the kernel
               based on the kernel command line. As with _DefaultEnvironment=_ ,
               this environment block is internal, and changes are not
               reflected in the manager's /proc/PID/environ.
    
               Setting environment variables for the manager process may be
               useful to modify its behaviour. See **Known Environment**
               **Variables******[3] for a descriptions of some variables understood
               by**systemd**.
    
               Simple "%"-specifier expansion is supported, see below for a
               list of supported specifiers.
    
               Added in version 248.
    
           _DefaultEnvironment=_
               Configures environment variables passed to all executed
               processes. Takes a space-separated list of variable
               assignments. See environ(7) for details about environment
               variables.
    
               Simple "%"-specifier expansion is supported, see below for a
               list of supported specifiers.
    
               Example:
    
                   DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"
    
               Sets three variables "VAR1", "VAR2", "VAR3".
    
               Added in version 205.
    


## SPECIFIERS



           Specifiers may be used in the _DefaultEnvironment=_ and
           _ManagerEnvironment=_ settings. The following expansions are
           understood:
    
           **Table 1. Specifiers available**
           ┌───────────┬──────────────────┬────────────────────────┐
           │ **Specifier** │ **Meaning** │ **Details** │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%a"      │ Architecture     │ A short string         │
           │           │                  │ identifying the        │
           │           │                  │ architecture of        │
           │           │                  │ the local system.      │
           │           │                  │ A string such as       │
           │           │                  │ **x86** , **x86-64** or         │
           │           │                  │ **arm64**. See the         │
           │           │                  │ architectures          │
           │           │                  │ defined for            │
           │           │                  │ _ConditionArchitecture=_ │
           │           │                  │ in systemd.unit(5)     │
           │           │                  │ for a full list.       │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%A"      │ Operating system │ The operating system   │
           │           │ image version    │ image version          │
           │           │                  │ identifier of the      │
           │           │                  │ running system, as     │
           │           │                  │ read from the          │
           │           │                  │ _IMAGE_VERSION=_ field   │
           │           │                  │ of /etc/os-release. If │
           │           │                  │ not set, resolves to   │
           │           │                  │ an empty string. See   │
           │           │                  │ os-release(5) for more │
           │           │                  │ information.           │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%b"      │ Boot ID          │ The boot ID of the     │
           │           │                  │ running system,        │
           │           │                  │ formatted as string.   │
           │           │                  │ See random(4) for more │
           │           │                  │ information.           │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%B"      │ Operating system │ The operating system   │
           │           │ build ID         │ build identifier of    │
           │           │                  │ the running system, as │
           │           │                  │ read from the          │
           │           │                  │ _BUILD_ID=_ field of     │
           │           │                  │ /etc/os-release. If    │
           │           │                  │ not set, resolves to   │
           │           │                  │ an empty string. See   │
           │           │                  │ os-release(5) for more │
           │           │                  │ information.           │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%H"      │ Host name        │ The hostname of the    │
           │           │                  │ running system.        │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%l"      │ Short host name  │ The hostname of the    │
           │           │                  │ running system,        │
           │           │                  │ truncated at the first │
           │           │                  │ dot to remove any      │
           │           │                  │ domain component.      │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%m"      │ Machine ID       │ The machine ID of the  │
           │           │                  │ running system,        │
           │           │                  │ formatted as string.   │
           │           │                  │ See machine-id(5) for  │
           │           │                  │ more information.      │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%M"      │ Operating system │ The operating system   │
           │           │ image identifier │ image identifier of    │
           │           │                  │ the running system, as │
           │           │                  │ read from the          │
           │           │                  │ _IMAGE_ID=_ field of     │
           │           │                  │ /etc/os-release. If    │
           │           │                  │ not set, resolves to   │
           │           │                  │ an empty string. See   │
           │           │                  │ os-release(5) for more │
           │           │                  │ information.           │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%o"      │ Operating system │ The operating system   │
           │           │ ID               │ identifier of the      │
           │           │                  │ running system, as     │
           │           │                  │ read from the _ID=_      │
           │           │                  │ field of               │
           │           │                  │ /etc/os-release. See   │
           │           │                  │ os-release(5) for more │
           │           │                  │ information.           │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%v"      │ Kernel release   │ Identical to **uname -r** │
           │           │                  │ output.                │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%w"      │ Operating system │ The operating system   │
           │           │ version ID       │ version identifier of  │
           │           │                  │ the running system, as │
           │           │                  │ read from the          │
           │           │                  │ _VERSION_ID=_ field of   │
           │           │                  │ /etc/os-release. If    │
           │           │                  │ not set, resolves to   │
           │           │                  │ an empty string. See   │
           │           │                  │ os-release(5) for more │
           │           │                  │ information.           │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%W"      │ Operating system │ The operating system   │
           │           │ variant ID       │ variant identifier of  │
           │           │                  │ the running system, as │
           │           │                  │ read from the          │
           │           │                  │ _VARIANT_ID=_ field of   │
           │           │                  │ /etc/os-release. If    │
           │           │                  │ not set, resolves to   │
           │           │                  │ an empty string. See   │
           │           │                  │ os-release(5) for more │
           │           │                  │ information.           │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%T"      │ Directory for    │ This is either /tmp or │
           │           │ temporary files  │ the path "$TMPDIR",    │
           │           │                  │ "$TEMP" or "$TMP" are  │
           │           │                  │ set to. (Note that the │
           │           │                  │ directory may be       │
           │           │                  │ specified without a    │
           │           │                  │ trailing slash.)       │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%V"      │ Directory for    │ This is either         │
           │           │ larger and       │ /var/tmp or the path   │
           │           │ persistent       │ "$TMPDIR", "$TEMP" or  │
           │           │ temporary files  │ "$TMP" are set to.     │
           │           │                  │ (Note that the         │
           │           │                  │ directory may be       │
           │           │                  │ specified without a    │
           │           │                  │ trailing slash.)       │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%h"      │ User home        │ This is the home       │
           │           │ directory        │ directory of the _user_  │
           │           │                  │ _running the service_    │
           │           │                  │ _manager instance_.      │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%u"      │ Username         │ This is the username   │
           │           │                  │ of the _user running_    │
           │           │                  │ _the service manager_    │
           │           │                  │ _instance_.              │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%U"      │ User id          │ This is the user id of │
           │           │                  │ the _user running the_   │
           │           │                  │ _service manager_        │
           │           │                  │ _instance_.              │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%g"      │ Primary group    │ This is the primary    │
           │           │                  │ group of the _user_      │
           │           │                  │ _running the service_    │
           │           │                  │ _manager instance_.      │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%G"      │ Primary group id │ This is the primary    │
           │           │                  │ group id of the _user_   │
           │           │                  │ _running the service_    │
           │           │                  │ _manager instance_.      │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%s"      │ User shell       │ This is the shell of   │
           │           │                  │ the _user running the_   │
           │           │                  │ _service manager_        │
           │           │                  │ _instance_.              │
           ├───────────┼──────────────────┼────────────────────────┤
           │ "%%"      │ Single percent   │ Use "%%" in place of   │
           │           │ sign             │ "%" to specify a       │
           │           │                  │ single percent sign.   │
           └───────────┴──────────────────┴────────────────────────┘
    


## NOTES



            1. 💣💥🧨💥💥💣 Please note that those configuration files must
               be available at all times. If /usr/local/ is a separate
               partition, it may not be available during early boot, and must
               not be used for configuration.
    
            2. No New Privileges Flag
               https://docs.kernel.org/userspace-api/no_new_privs.html
    
            3. Known Environment Variables
               https://systemd.io/ENVIRONMENT
    


* * *