## Name

dbus-monitor — debug probe to print message bus messages

## Synopsis

`dbus-monitor` [ --system | --session | --address `ADDRESS` ] [ --profile | --monitor | --pcap | --binary ] [ `watch` `expressions` ]

## DESCRIPTION

The dbus-monitor command is used to monitor messages going through a D-Bus message bus. See https://www.freedesktop.org/wiki/Software/dbus/ for more information about the big picture.

There are two well-known message buses: the systemwide message bus (installed on many systems as the "messagebus" service) and the per-user-login-session message bus (started each time a user logs in). The --system and --session options direct dbus-monitor to monitor the system or session buses respectively. If neither is specified, dbus-monitor monitors the session bus.

dbus-monitor has two different text output modes: the 'classic'-style monitoring mode, and profiling mode. The profiling format is a compact format with a single line per message and microsecond-resolution timing information. The --profile and --monitor options select the profiling and monitoring output format respectively.

dbus-monitor also has two binary output modes. The binary mode, selected by `--binary`, outputs the entire binary message stream (without the initial authentication handshake). The PCAP mode, selected by `--pcap`, adds a PCAP file header to the beginning of the output, and prepends a PCAP message header to each message; this produces a binary file that can be read by, for instance, Wireshark.

If no mode is specified, dbus-monitor uses the monitoring output format.

In order to get dbus-monitor to see the messages you are interested in, you should specify a set of watch expressions as you would expect to be passed to the dbus_bus_add_match function.

The message bus configuration may keep dbus-monitor from seeing all messages, especially if you run the monitor as a non-root user.

## OPTIONS

`--system`

  Monitor the system message bus.

`--session`

  Monitor the session message bus. (This is the default.)

`--address ADDRESS`

  Monitor an arbitrary message bus given at ADDRESS.

`--profile`

  Use the profiling output format.

`--monitor`

  Use the monitoring output format. (This is the default.)

## EXAMPLE

Here is an example of using dbus-monitor to watch for the gnome typing monitor to say things

dbus-monitor "type='signal',sender='org.gnome.TypingMonitor',interface='org.gnome.TypingMonitor'"

## AUTHOR

dbus-monitor was written by Philip Blundell. The profiling output mode was added by Olli Salli.

## BUGS

Please send bug reports to the D-Bus mailing list or bug tracker, see https://www.freedesktop.org/wiki/Software/dbus/