notifyutil(1) General Commands Manual notifyutil(1)
notifyutil – notification command line utility
notifyutil [-q] [-v] [-z msec] [-M] [-R] [command ...]
notifyutil is a command-line utility for interacting with the notify(3)
notification system and the notifyd(8) server. It may be used to post
notifications, detect and report notifications, and to examine and set the
state values associated with notification keys.
If notifyutil is used to monitor one or more notification keys, it prints
the notification key when the corresponding notification is received. The
-v (verbose) and -q (quiet) flags, if specified, modify the output
The -v flag causes notifyutil to print a time stamp, the notification key,
the current state value for that key, and the type of the notification
(port, file, etc). The -q flag supresses any output except for state
values fetched following a -g command.
Commands listed in the table below are processed in left to right order
from the command line.
-p key Post a notification for key.
-w key Register for key and wait forever for notifications.
-# key Register for key and wait for # (an integer)
E.g. -1 key waits for a single notification.
-g key Get state value for key.
-s key val Set state value for key.
-port Use mach port notifications for subsequent -w or -#
This is the default registration type.
-file Use file descriptor notifications for subsequent
-check Use shared memory notifications for subsequent
-signal [#] Use signal notifications for subsequent registrations.
Signal 1 (HUP) is the default, but an alternate signal
may be specified.
-dispatch Use dispatch for subsequent registrations.
When invoked with any combination of -w and -# actions, notifyutil
registers for notification for the specified key(s). If any key is given
with a -w action, notifyutil runs until interrupted with Control-C. If all
registrations are invoked with -#, the program continues to run until the
corresponding number of notifications for each key have been received.
By default, notifyutil uses mach port registration (using
notify_register_mach_port()) for keys given with a -w or -# flag. The
-file command causes notifyutil to use notify_register_file_descriptor()
for any subsequent -w or -# registrations. Similarly, -check causes
notifyutil to use notify_register_check() for subsequent registrations,
-signal switches to notify_register_signal(), and -dispatch causes it to
use notify_register_dispatch() for subsequent registrations.
If any registrations are made following the use of the -check command,
notifyutil will start a timer and check for shared memory notifications
every 100 milliseconds. An alternate timer value may be set following the
The -M flag causes notifyutil to use multiplex all notifications over a
single mach connection with notifyd. Notifications (except shared memory
notifications) are received and redistributed by a dispatch handler.
The -R flag causes notifyutil to regenerate all its registrations in the
unlikely event that notifyd restarts.
Note that a notification key and its associated state variable only exist
when there are one or more current registrations for that key. Setting the
state for a key that has no registrations has no effect. Thus the command
notifyutil -s foo.bar 123 -g foo.bar
unless foo.bar is registered by some other process. However, the command
notifyutil -w foo.bar -s foo.bar 123 -g foo.bar
since the “-w foo.bar” registration ensures the key and its state variable
exist before the value is set, and continue to exist when the value is
Mac OS X November 4, 2011 Mac OS X