systemd-notify - Notify service manager about start-up completion and other
daemon status changes
systemd-notify may be called by daemon scripts to notify the init system
about status changes. It can be used to send arbitrary information, encoded in
an environment-block-like list of strings. Most importantly, it can be used
for start-up completion notification.
This is mostly just a wrapper around sd_notify() and makes
this functionality available to shell scripts. For details see
The command line may carry a list of environment variables to send
as part of the status update.
Note that systemd will refuse reception of status updates from
this command unless NotifyAccess= is set for the service unit this
command is called from.
Note that sd_notify() notifications may be attributed to
units correctly only if either the sending process is still around at the
time PID 1 processes the message, or if the sending process is explicitly
runtime-tracked by the service manager. The latter is the case if the
service manager originally forked off the process, i.e. on all processes
that match NotifyAccess=main or
NotifyAccess=exec. Conversely, if an auxiliary process of the
unit sends an sd_notify() message and immediately exits, the service
manager might not be able to properly attribute the message to the unit, and
thus will ignore it, even if NotifyAccess=all is set for it.
When --no-block is used, all synchronization for reception of
notifications is disabled, and hence the aforementioned race may occur if
the invoking process is not the service manager or spawned by the service
Hence, systemd-notify will first attempt to invoke
sd_notify() pretending to have the PID of the invoking process. This
will only succeed when invoked with sufficient privileges. On failure, it
will then fall back to invoking it under its own PID. This behaviour is
useful in order that when the tool is invoked from a shell script the shell
process — and not the systemd-notify process — appears
as sender of the message, which in turn is helpful if the shell process is
the main process of a service, due to the limitations of
NotifyAccess=all. Use the --pid= switch to tweak this
The following options are understood:
Inform the init system about service start-up completion.
This is equivalent to systemd-notify READY=1
. For details about the
semantics of this option see sd_notify(3)
Inform the service manager about the main PID of the
daemon. Takes a PID as argument. If the argument is specified as
"auto" or omitted, the PID of the process that invoked
is used, except if that's the service manager. If the
argument is specified as "self", the PID of the
command itself is used, and if "parent" is
specified the calling process' PID is used — even if it is the service
manager. This is equivalent to systemd-notify MAINPID=$PID
. For details
about the semantics of this option see sd_notify(3)
Set the user ID to send the notification from. Takes a
UNIX user name or numeric UID. When specified the notification message will be
sent with the specified UID as sender, in place of the user the command was
invoked as. This option requires sufficient privileges in order to be able
manipulate the user identity of the process.
Send a free-form status string for the daemon to the init
systemd. This option takes the status string as argument. This is equivalent
to systemd-notify STATUS=...
. For details about the semantics of this
option see sd_notify(3)
Returns 0 if the system was booted up with systemd,
non-zero otherwise. If this option is passed, no message is sent. This option
is hence unrelated to the other options. For details about the semantics of
this option, see sd_booted(3)
. An alternate way to check for this state
is to call systemctl(1)
with the is-system-running
will return "offline" if the system was not booted with
Do not synchronously wait for the requested operation to
finish. Use of this option is only recommended when systemd-notify is
spawned by the service manager, or when the invoking process is directly
spawned by the service manager and has enough privileges to allow
systemd-notify to send the notification on its behalf. Sending
notifications with this option set is prone to race conditions in all other
Print a short help text and exit.
Print a short version string and exit.
On success, 0 is returned, a non-zero failure code otherwise.
Example 1. Start-up Notification and Status Updates
A simple shell daemon that sends start-up notifications after
having set up its communication channel. During runtime it sends further
status updates to the init system:
systemd-notify --ready --status="Waiting for data..."
while : ; do
read a < /tmp/waldo
systemd-notify --status="Processing $a"
# Do something with $a ...
systemd-notify --status="Waiting for data..."