View source for Dbus

Dbus is a messaging system used in Linux display managers such as GNOME. 

== Accessing Dbus ==
Dbus is accessed using a socket whose location is defined as an environment variable named {{code|DBUS_SESSION_BUS_ADDRESS}}. Typically, it will look something like:
{{highlight|lang=text|code=
DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-2L2ZxqLwNR,guid=9bf5b79ea33d45373491174856252e15
}}

This environment variable must be defined in order for Dbus utilities to work properly.

== Watching For Messages / Events ==
You can watch the dbus for messages using the {{code|dbus-monitor}} utility. A filter can be passed as an argument. For example, to limit only messages sent by the GNOME SessionManager:
{{highlight|lang=terminal|code=
dbus-monitor "type=signal,sender='org.gnome.SessionManager'"
}}

== Sending Messages ==
Messages can be sent using {{code|dbus call}} or {{code|dbus-send}}.

Eg:
{{highlight|lang=terminal|code=
gdbus call --session --dest org.gnome.SessionManager \
  --object-path /org/gnome/SessionManager/Presence \
  --method org.gnome.SessionManager.Presence.SetStatus 0
}}

== See Also ==
* http://dbus.freedesktop.org/doc/dbus-send.1.html

Gnome Presence Key
* https://people.gnome.org/~mccann/gnome-session/docs/gnome-session.html#org.gnome.SessionManager.Presence:status
Gnome Screensaver (doesn't seem to work)
* http://unix.stackexchange.com/questions/107787/how-can-i-trigger-the-screensavers-locking-feature-using-d-bus-from-the-command

[[Category:Linux]]