How do I change the default session I get when I log in? I'm on Debian jessie. I tried changing settings on gdm3, tried installing lightdm and following this but it's just not working.
For more specificity, I'm trying to default to gnome-classic instead of gnome. I want to turn on the computer, log in as any arbitrary user, and see gnome-classic, not gnome3 (preferably I'd remove the gnome3 default session, if there's a way to do that).
On Debian, you should set the x-session-manager default command to choose your default session manager:
# update-alternatives --config x-session-manager
There, you can select the session manager you want GDM3 to use by default.
If gnome-session-classic does not appear in the listing, try creating the link on your own. Something like the following:
# update-alternatives --install /usr/bin/x-session-manager x-session-manager /usr/bin/gnome-session-classic 60
Then you should be able to select gnome-classic with update-alternatives --config x-session-manager.
To customize the session managers listed by GDM, I think the only way is to go to /usr/share/xsessions and create/remove Desktop Entry files there. The format is easy to understand, but in case you need help, you can consult the Desktop Entry specification or the GNOME documentation about Desktop Entry files.
With GDM, have you tried modifying your ~/.dmrc file? You can set gnome classic as your default session like this:
[Desktop]
Session=gnome-classic
reference: GDM manual
try to edit /etc/gdm/custom.conf:
[daemon]
DefaultSession=gnome-classic
but I think that by default it will offer you the last used for that user anyway...
if you want to select default x-session
sudo update-alternatives --config x-session-manager
if you want to remove x-session options first list their path by
update-alternatives --list x-session-manager
then remove option by
sudo update-alternatives --remove x-session-manager /usr/bin/gnome-session
