I have Googled this one and tried so many combinations, with no success.
I need the GDM login greeter to display one and only one username. In effect, what I need is something like this in /etc/gdm/custom.conf:
[greeter]
ExcludeAll=true
Include=guest
This does not work, however, because ExcludeAll is not a valid option. IncludeAll=false does nothing either. I've tried every combination that I can think of.
Despite being discouraged, I modified /etc/gdm/gdm.schemas, trying a variety of combinations similar to the above. No go.
I am aware of:
gconftool-2 --config-source xml:readwrite:/etc/gconf/gconf.xml.defaults --direct --type bool --set /apps/gdm/simple-greeter/disable_user_list true
but this is not an applicable solution, as it removes the user list completely. I need one specific username to appear.
The only practical solution I can find is to, upon user login, run a script which will append that username to the "Exclude" list in /etc/gdm/custom.conf. This is hacky, and not preferable.
This is for a public-use machine. People can log in with their LDAP accounts if they have them, or they can select "Guest" from the login screen. The people who log in with their LDAP accounts should NOT have their names visible on the login screen, but the "Guest" option must remain.
Using gnome 2.28.
Best Answer
Instead of hiding all but one user why can you not create just 1 user for all lab pc's, and install that user locally on each machine? Then enable sharing this way:
If a user is on the LDAP Server allow the user to login to devices etc while logged in as guest, by providing their LDAP credentials, only when needed instead of allowing them to login via GDM