Ubuntu Manpage: gnome-session - Start the GNOME desktop environment

Provided by: gnome-session-bin_46.0-1ubuntu4_amd64

NAME

       gnome-session - Start the GNOME desktop environment

SYNOPSIS

       gnome-session [-a|--autostart=DIR] [--session=SESSION] [--failsafe|-f] [--debug] [--whale]

DESCRIPTION

       The  gnome-session program starts up the GNOME desktop environment. This command is typically executed by
       your login manager (either gdm, xdm, or from your X startup scripts). It  will  load  either  your  saved
       session, or it will provide a default session for the user as defined by the system administrator (or the
       default  GNOME  installation  on  your  system).  Note  that gnome-session is a wrapper script for gnome-
       session-binary.

       The  default  session  is  defined  in  gnome.session,  a  .desktop-like  file  that  is  looked  for  in
       $XDG_CONFIG_HOME/gnome-session/sessions,            $XDG_CONFIG_DIRS/gnome-session/sessions           and
       $XDG_DATA_DIRS/gnome-session/sessions.

       When  saving   a   session,   gnome-session   saves   the   currently   running   applications   in   the
       $XDG_CONFIG_HOME/gnome-session/saved-session directory. Saving sessions is only supported with the legacy
       non-systemd startup method.

       gnome-session  is  an  X11R6  session  manager.  It can manage GNOME applications as well as any X11R6 SM
       compliant application.

OPTIONS

       The following options are supported:

       --autostart=DIR
              The directory DIR to be searched for autostart .desktop files. This option can  be  used  multiple
              times.  When this option is present, then default autostart directories will not be searched.

       --session=SESSION
              Use the applications defined in SESSION.session. If not specified, gnome.session will be used.

       --failsafe
              Run in fail-safe mode. User-specified applications will not be started.

       --debug
              Enable debugging code.

       --whale
              Show the fail whale in a dialog for debugging it.

SESSION DEFINITION

       Sessions are defined in .session files, that are using a .desktop-like format, with the following keys in
       the GNOME Session group:

       Name   Name of the session. This can be localized.

       RequiredComponents
              List  of  component  identifiers  (desktop  files)  that are required by the session. The required
              components will always run in the session.

       Here is an example of a session definition:

           [GNOME Session]
           Name=GNOME
           RequiredComponents=gnome-shell;gnome-settings-daemon;

       In systemd managed sessions the RequiredComponents may be provided by systemd units instead. In this case
       the corresponding .desktop file needs  to  contain  X-GNOME-HiddenUnderSystemd=true.  gnome-session  will
       ignore  these  components  and  rely  on  systemd  to manage them appropriately, see the systemd for more
       information on how this works.

       The .session files are looked  for  in  $XDG_CONFIG_HOME/gnome-session/sessions,  $XDG_CONFIG_DIRS/gnome-
       session/sessions and $XDG_DATA_DIRS/gnome-session/sessions.

systemd

gnome-session can pass much of the session management over to systemd. In this case, startup components
that have X-GNOME-HiddenUnderSystemd=true set in their .desktop file will be ignored by gnome-session. It
instead relies on the fact that these components are managed by systemd.

systemd provides the two special targets graphical-session.target and graphical-session-pre.target which
are fully functional and should be used. gnome-session provides the following main targets:

gnome-session.target
Generic unit that will be active throughout the session. Similar to graphical-session.target.

gnome-session-pre.target
Used for tasks that need to be done before session startup. Similar to graphical-session-
pre.target.

gnome-session-x11@SESSION.target gnome-session-wayland@SESSION.target
Main unit started for X11/wayland based session. SESSION is set according to the session that is
passed in --session.

gnome-session-x11.target gnome-session-wayland.target
Convenience units without the session embedded into the target.

gnome-session@SESSION.target
Convenience unit with just the SESSION information embedded.

gnome-session-x11-services.target
Special unit started when X11 services are needed. This will be used from GNOME 3.36 onwards.
Programs will need to use the special GNOME_SETUP_DISPLAY environment variable instead of DISPLAY.

Note that care must be taken to set appropriate After= rules. It is also strongly recommended to always
do this in combination with BindsTo= or PartOf= on one of the core targets (e.g. graphical-
session.target).

Units are required to set CollectMode=inactive-or-failed. In addition, it is strongly recommended to set
TimeoutStopSec=5 so that logout will not be delayed indefinitely in case the process does not stop
properly.

ENVIRONMENT

       gnome-session sets several environment variables for the use of its child processes:

       SESSION_MANAGER

              This variable is used by session-manager aware clients to contact gnome-session.

       DISPLAY

              This variable is set to the X display being used by gnome-session.  Note  that  if  the  --display
              option  is  used  this might be different from the setting of the environment variable when gnome-
              session is invoked.

       Behavior of gnome-session ifself can be modified via the following environment variable:

       GNOME_SESSION_AUTOSTART_DIR

              This variable specifies a list of directories to the searched for autostart files.  This  variable
              overrides  all  directories specified via the --autostart option, as well as all default autostart
              directories.

FILES

       $XDG_CONFIG_HOME/autostart $XDG_CONFIG_DIRS/autostart /usr/share/gnome/autostart

              Applications defined via .desktop files in those directories will be  started  on  login.   gnome-
              session-properties(1) can be used to easily configure them.

       $XDG_CONFIG_HOME/gnome-session/sessions   $XDG_CONFIG_DIRS/gnome-session/sessions   $XDG_DATA_DIRS/gnome-
       session/sessions

              These directories contain the .session files that can be used with the --session option.

       $XDG_CONFIG_HOME/gnome-session/saved-session

              This directory contains the list of applications of the saved session.

BUGS

       If    you    find    bugs    in    the    gnome-session    program,    please     report     these     on
       https://gitlab.gnome.org/GNOME/gnome-session/issues.