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dbus-launch(1)				  User Commands 			   dbus-launch(1)

       dbus-launch - Utility to start a message bus from a shell script

       dbus-launch   [--auto-syntax]   [--config-file=filename]  [--close-stderr]  [--csh-syntax]
       [--exit-with-session] [--help] [--sh-syntax] [--version]

       The dbus-launch command is used to start a session bus  instance  of  dbus-daemon  from	a
       shell script.  It would normally be called from a user's login scripts.	Unlike the daemon
       itself, dbus-launch exits, so backticks or the $() construct can be used to read  informa-
       tion from dbus-launch.

       With  no  arguments,  dbus-launch will launch a session bus instance and print the address
       and pid of that instance to standard output.

       You may specify a program to be run; in this case, dbus-launch will launch a  session  bus
       instance,  set the appropriate environment variables so the specified program can find the
       bus, and then execute the specified program, with the specified arguments.  See below  for

       If  you	launch a program, dbus-launch will not print the information about the new bus to
       standard output.

       When dbus-launch prints bus information to standard output, by default it is in	a  simple
       key-value  pairs  format.   However,  you may request several alternate syntaxes using the
       --sh-syntax, --csh-syntax, --binary-syntax, or --auto-syntax options.   Several	of  these
       cause dbus-launch to emit shell code to set up the environment.

       With  the  --auto-syntax  option,  dbus-launch looks at the value of the SHELL environment
       variable to determine which shell syntax should be used.  If SHELL  ends  in  "csh",  then
       csh-compatible  code is emitted; otherwise Bourne shell code is emitted.  Instead of pass-
       ing --auto-syntax, you may explicity specify a particular one  by  using  --sh-syntax  for
       Bourne  syntax,	or  --csh-syntax  for csh syntax.  In scripts, it is more robust to avoid
       --auto-syntax and you hopefully know which shell your script is written in.

       See http://www.freedesktop.org/software/dbus/ for more information about D-Bus.	Also  see
       the man page for dbus-daemon.

       If  DBUS_SESSION_BUS_ADDRESS  is not set for a process that tries to use D-Bus, by default
       the process will attempt to invoke dbus-launch with the --autolaunch option to start up	a
       new  session  bus  or  find  the  existing  bus	address  on the X display or in a file in

       Whenever an autolaunch occurs, the application that had to start a new bus will be in  its
       own  little  world;  it can effectively end up starting a whole new session if it tries to
       use a lot of bus services. This can be suboptimal or even totally broken, depending on the
       application and what it tries to do.

       There  are  two	common reasons for autolaunch. One is ssh to a remote machine.	The ideal
       fix for that would be forwarding of DBUS_SESSION_BUS_ADDRESS in the same way that  DISPLAY
       is  forwarded.	In  the  meantime, you can edit the session.conf config file to have your
       session bus listen on TCP, and manually set DBUS_SESSION_BUS_ADDRESS, if you like.

       The second common reason for autolaunch is an su(1m).  to another user, and display  of	X
       applications  running  as the second user on the display belonging to the first user. Per-
       haps the ideal fix in this case would be to allow the second user to connect to	the  ses-
       sion  bus  of  the first user, just as they can connect to the first user's display.  How-
       ever, a mechanism for that has not been coded.

       You can always avoid autolaunch by manually setting DBUS_SESSION_BUS_ADDRESS.   Autolaunch
       happens	because  the  default  address (if none is set) is "autolaunch:", so if any other
       address is set there will be no autolaunch.  You can  however  include  autolaunch  in  an
       explicit  session  bus  address as a fallback, for example DBUS_SESSION_BUS_ADDRESS="some-
       thing:,autolaunch:" - in that case if the first address doesn't work, processes will auto-
       launch. (The bus address variable contains a comma-separated list of addresses to try.)

       The --autolaunch option is considered an internal implementation detail of libdbus, and in
       fact there are plans to change it.  There is no real reason to use it outside of the libd-
       bus implementation anyhow.

       The following options are supported:


	   This  option implies that dbus-launch should scan for a previously-started session and
	   reuse the values found there.  If no session is found, it will start  a  new  session.
	   The	--exit-with-session  option  is implied if --autolaunch is given.  This option is
	   for the exclusive use of libdbus, you do not want to use it manually.  It  may  change
	   in the future.


	   Choose --csh-syntax or --sh-syntax based on the SHELL environment variable.


	   Write  to stdout a nul-terminated bus address, then the bus PID as a binary integer of
	   size sizeof(pid_t), then the bus X window ID as a binary integer of size sizeof(long).
	   Integers  are in the machine's byte order, not network byte order or any other canoni-
	   cal byte order.


	   Close the standard error output stream before starting the D-Bus daemon.  This is use-
	   ful	if you want to capture dbus-launch error messages but you do not want dbus-daemon
	   to keep the stream open to your application.


	   Pass --config-file=filename to the bus daemon, instead of  passing  it  the	--session
	   argument.  See the man page for dbus-daemon.


	   Emit csh compatible code to set up environment variables.


	   If  this  option  is  provided, a persistent "babysitter" process will be created that
	   watches stdin for HUP and tries to connect to the X server.	If this  process  gets	a
	   HUP on stdin or loses its X connection, it kills the message bus daemon.

       -?, --help

	   Show help information on standard output and exit.


	   Emit Bourne-shell compatible code to set up environment variables.


	   Print the version of dbus-launch.

       Example	1: How to use dbus-launch with a sh-compatible shell to start the per-session bus

	      ## test for an existing bus daemon, just to be safe
	      if test -z "$DBUS_SESSION_BUS_ADDRESS" ; then
		  ## if not found, launch a new one
		  eval `dbus-launch --sh-syntax --exit-with-session`
		  echo "D-Bus per-session daemon address is: $DBUS_SESSION_BUS_ADDRESS"

       Example 2: Use dbus-launch to run your main session program

	      example% dbus-launch --exit-with-session gnome-session

       The above would likely be appropriate for ~/.xsession or ~/.Xclients.

       See environ(5) for descriptions of the following environment variables:


	   The address of the login session message bus.  If this variable is not  set,  applica-
	   tions  may  also try to read the address from the X Window System root window property
	   _DBUS_SESSION_BUS_ADDRESS.  The root window property must have type STRING.	The envi-
	   ronment variable should have precedence over the root window property.


	   Set	DBUS_VERSION=1 to enable debugging, if D-Bus was compiled with verbose debug mode


	   When the --auto-syntax is used, then dbus-launch checks the	SHELL  environment  vari-
	   able.   If  it ends in "csh", then the --csh-syntax option will be used, otherwise the
	   --sh-syntax will be used.

       The following exit values are returned:

       0	Application exited successfully

       >0	Application exited with failure

       The following files are used by this application:

       /usr/bin/dbus-launch	       Executable for dbus-launch

       /etc/dbus-1/session.conf        Configuration file for D-Bus session services.

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWdbus			   |
       |Interface stability	     |Volatile			   |

       dbus-cleanup-sockets(1), dbus-daemon(1), dbus-monitor(1),  dbus-send(1),  dbus-uuidgen(1),
       libdbus-glib-1(3), attributes(5), environ(5)

       For  authorship information refer to http://www.freedesktop.org/software/dbus/doc/AUTHORS.
       Updated by Brian Cameron, Sun Microsystems Inc., 2007.

       Please send bug reports to the D-Bus mailing list or bug tracker, see http://www.freedesk-

SunOS 5.11				   19 Nov 2007				   dbus-launch(1)
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