With the --systemd option, if an instance of systemd --user is available on D-Bus, it also updates the list of environment variables used by systemd --user when it activates user services, including D-Bus session services for which dbus-daemon has been configured to delegate activation to systemd. This is very similar to the import-environment command provided by systemctl(1)).
Variables that are special to dbus-daemon or systemd may be set, but their values will be overridden when a service is started. For instance, it is not useful to add DBUS_SESSION_BUS_ADDRESS to dbus-daemon's activation environment, although it might still be useful to add it to systemd's activation environment.
dbus-update-activation-environment is primarily designed to be used in Linux distributions' X11 session startup scripts, in conjunction with the "user bus" design.
To propagate DISPLAY and XAUTHORITY to dbus-daemon and, if present, systemd, and propagate DBUS_SESSION_BUS_ADDRESS to systemd:
dbus-update-activation-environment --systemd \ DBUS_SESSION_BUS_ADDRESS DISPLAY XAUTHORITY
To propagate all environment variables except XDG_SEAT, XDG_SESSION_ID and XDG_VTNR to dbus-daemon (and, if present, systemd) for compatibility with legacy X11 session startup scripts:
# in a subshell so the variables remain set in the # parent script ( unset XDG_SEAT unset XDG_SESSION_ID unset XDG_VTNR dbus-update-activation-environment --systemd --all )
dbus-update-activation-environment exits with status 0 on success, EX_USAGE (64) on invalid command-line options, EX_OSERR (71) if unable to connect to the session bus, or EX_UNAVAILABLE (69) if unable to set the environment variables. Other nonzero exit codes might be added in future versions.
dbus-daemon does not provide a way to unset environment variables after they have been set (although systemd does), so dbus-update-activation-environment does not offer this functionality either.
POSIX does not specify the encoding of non-ASCII environment variable names or values and allows them to contain any non-zero byte, but neither dbus-daemon nor systemd supports environment variables with non-UTF-8 names or values. Accordingly, dbus-update-activation-environment assumes that any name or value that appears to be valid UTF-8 is intended to be UTF-8, and ignores other names or values with a warning.
Please send bug reports to the D-Bus bug tracker or mailing list. See m[blue]http://www.freedesktop.org/software/dbus/m.
This man page is distributed under the same terms as dbus-update-activation-environment (MIT/X11). There is NO WARRANTY, to the extent permitted by law.