.\"
.\" gnome-session manual page.
.\" (C) 2000 Miguel de Icaza (miguel@helixcode.com)
.\" (C) 2009-2010 Vincent Untz (vuntz@gnome.org)
.\" (C) 2019 Benjamin Berg (bberg@redhat.com)
.\" (C) 2020 Sebastian Geiger (sbastig@gmx.net)
.\"
.TH GNOME-SESSION 1 "May 2020" "GNOME"
.SH NAME
gnome-session \- Start the GNOME desktop environment
.SH SYNOPSIS
.B gnome-session [\-a|\-\-autostart=DIR] [\-\-session=SESSION] [\-\-failsafe|\-f] [\-\-debug] [\-\-whale]
.SH DESCRIPTION
The \fIgnome-session\fP 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 \fIgnome-session\fP is a wrapper
script for \fIgnome-session-binary\fP.
.PP
The default session is defined in \fBgnome.session\fP, a .desktop-like
file that is looked for in
\fB$XDG_CONFIG_HOME/gnome-session/sessions\fP,
\fB$XDG_CONFIG_DIRS/gnome-session/sessions\fP and
\fB$XDG_DATA_DIRS/gnome-session/sessions\fP.
.PP
When saving a session, \fIgnome-session\fP saves the currently running
applications in the \fB$XDG_CONFIG_HOME/gnome-session/saved-session\fP
directory. Saving sessions is only supported with the legacy non-systemd
startup method.
.PP
\fIgnome-session\fP is an X11R6 session manager. It can manage GNOME
applications as well as any X11R6 SM compliant application.
.SH OPTIONS
The following options are supported:
.TP
.I "--autostart=DIR"
The directory \fBDIR\fP 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.
.TP
.I "--session=SESSION"
Use the applications defined in \fBSESSION.session\fP. If not specified,
\fBgnome.session\fP will be used.
.TP
.I "--builtin"
Use the legacy non-systemd method of managing the user session. This is the
opposite of the \fI--systemd\fP option.
.TP
.I "--systemd"
Use the systemd method of managing the user session. This is the opposite of
the \fI--builtin\fP option.
.TP
.I "--failsafe"
Run in fail-safe mode. User-specified applications will not be started.
.TP
.I "--debug"
Enable debugging code.
.TP
.I "--whale"
Show the fail whale in a dialog for debugging it.
.SH SESSION DEFINITION
Sessions are defined in \fB.session\fP files, that are using a .desktop-like
format, with the following keys in the \fBGNOME Session\fP group:
.TP
.I Name
Name of the session. This can be localized.
.TP
.I RequiredComponents
List of component identifiers (desktop files) that are required by the session. The required components will always run in the session.
.PP
Here is an example of a session definition:
.PP
.in +4n
.nf
[GNOME Session]
Name=GNOME
RequiredComponents=gnome-shell;gnome-settings-daemon;
.in
.fi
.PP
In \fBsystemd\fP managed sessions the RequiredComponents may be provided by
systemd units instead. In this case the corresponding \fB.desktop\fP file needs
to contain \fBX-GNOME-HiddenUnderSystemd=true\fP. \fIgnome-session\fP will
ignore these components and rely on \fIsystemd\fP to manage them appropriately,
see the \fIsystemd\fP for more information on how this works.
.PP
The \fB.session\fP files are looked for in
\fB$XDG_CONFIG_HOME/gnome-session/sessions\fP,
\fB$XDG_CONFIG_DIRS/gnome-session/sessions\fP and
\fB$XDG_DATA_DIRS/gnome-session/sessions\fP.
.SH systemd
\fIgnome-session\fP can pass much of the session management over to systemd
(see the \fI--systemd\fP option which may be the default since 3.34). In this
case, startup components that have \fBX-GNOME-HiddenUnderSystemd=true\fP
set in their \fB.desktop\fP file will be ignored by \fIgnome-session\fP. It
instead relies on the fact that these components are managed by systemd.
.PP
As of GNOME 3.34 the systemd support is new and the customizing the
configuration is not yet easily possible. With GNOME 3.34 it may be best to use
\fI--builtin\fP if session customizations are required. This is due to the way
that GNOME currently defines the components that will be started on each session
type.
.PP
\fBsystemd\fP provides the two special targets \fBgraphical-session.target\fP
and \fBgraphical-session-pre.target\fP which are fully functional and should be
used. \fIgnome-session\fP provides the following main targets:
.TP
.I "gnome-session.target"
Generic unit that will be active throughout the session. Similar to
\fBgraphical-session.target\fP.
.TP
.I "gnome-session-pre.target"
Used for tasks that need to be done before session startup. Similar to
\fBgraphical-session-pre.target\fP.
.TP
.I "gnome-session-x11@SESSION.target" "gnome-session-wayland@SESSION.target"
Main unit started for X11/wayland based session. \fBSESSION\fP is set according
to the session that is passed in \fI--session\fP.
.TP
.I "gnome-session-x11.target" "gnome-session-wayland.target"
Convenience units without the session embedded into the target.
.TP
.I "gnome-session@SESSION.target"
Convenience unit with just the \fBSESSION\fP information embedded.
.TP
.I "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 \fBGNOME_SETUP_DISPLAY\fP
environment variable instead of \fIDISPLAY\fP.
.PP
Note that care must be taken to set appropriate \fBAfter=\fP rules. It is also
strongly recommended to always do this in combination with \fBBindsTo=\fP or
\fBPartOf=\fP on one of the core targets (e.g. \fBgraphical-session.target\fP).
.PP
Units are required to set \fBCollectMode=inactive-or-failed\fP. In addition, it
is strongly recommended to set \fBTimeoutStopSec=5\fP so that logout
will not be delayed indefinitely in case the process does not stop properly.
.SH ENVIRONMENT
\fIgnome-session\fP sets several environment variables for the use of
its child processes:
.PP
.B SESSION_MANAGER
.IP
This variable is used by session-manager aware clients to contact
gnome-session.
.PP
.B DISPLAY
.IP
This variable is set to the X display being used by
\fIgnome-session\fP. Note that if the \fI--display\fP option is used
this might be different from the setting of the environment variable
when gnome-session is invoked.
.PP
Behavior of \fIgnome-session\fP ifself can be modified via the following environment variable:
.PP
.B GNOME_SESSION_AUTOSTART_DIR
.IP
This variable specifies a list of directories to the searched for autostart
files. This variable overrides all directories specified via the
\fI--autostart\fP option, as well as all default autostart directories.
.SH FILES
.PP
.B $XDG_CONFIG_HOME/autostart
.B $XDG_CONFIG_DIRS/autostart
.B /usr/share/gnome/autostart
.IP
Applications defined via .desktop files in those directories will be started on login.
.PP
.B $XDG_CONFIG_HOME/gnome-session/sessions
.B $XDG_CONFIG_DIRS/gnome-session/sessions
.B $XDG_DATA_DIRS/gnome-session/sessions
.IP
These directories contain the \fB.session\fP files that can be used
with the \fI--session\fP option.
.PP
.B $XDG_CONFIG_HOME/gnome-session/saved-session
.IP
This directory contains the list of applications of the saved session.
.SH BUGS
If you find bugs in the \fIgnome-session\fP program, please report
these on https://gitlab.gnome.org/GNOME/gnome-session/issues.
.SH SEE ALSO
.BR gnome-session-quit(1)