So, Linux is supposed to be configurable. You are supposed to be able to change things very easily by editing a file or running a command. One of the commands which is wild and wacky is “update-alternatives”. But what I wanted to do was to reset the login manager’s background to what I have as a desktop background. I found a few sites which told me different ways to do it like here and here. I figured that Ubuntu was pretty darned close; hence the second link. But it ain’t and it don’t work on Debian Testing.
Then I started looking more. There is an over-ride file which takes precedence over the other settings in the links. This resource pretty much spells out what you need to do to make a change. In essence, you must edit the /usr/share/gdm/greeter-settings/xy_desktop-base.gschema.override file and make a change there. You may need to do a dpkg-reconfigure gdm3 to make the thing reread the configurations. In essence, the file looks like this:
Kinda strange eh? So, all I did was to replace the the second line and comment it out. This is not an elegant solution since if I change the background, I’ll have to remember all this again (and again, again, etc).
Perhaps it just goes to point out that Linux is configurable and flexible but sometimes it ain’t where or what you think it is. No matter what, its a learning experience with Linux and how things are either written, stored, or configured. I figure about 90% of all the files that do stuff on Linux are flat text files anyways. That makes it pretty handy for changing since a text editor comes with everything under the sun. No registry hives with the arcane windows registry editors.
I was talking to a person who I respect in the Linux space awhile ago about this stuff. We both were laughing about how absurdly easy it is to either add things to a very important file like /etc/fstab or make the entire system go bonkers. Let your editor wrap the right margin to the next line and files like /etc/fstab, etc/samba/smb.conf, and others will play all sorts of games. Its the advantage and the hazard and perhaps that’ s why the modern Linux distributions try so hard to give graphical tools to do things. People still edit those pesky text files though. I still use “apt-get” for most things or “aptitude”.
If you want to change a background in your login manager, my answer most likely is not yours. It may work today but not tomorrow and it may get over-written so I am still hunting for a better way of doing this. Its time to drop someone like JimD an email and ask. JimD knows. Linux.