ubuntu wiki LightDM states:

LighDM configuration is governed by the lightdm.conf file, however it's not suppose to be directly edited, instead use:


$ lightdm-set-defaults
lightdm-set-defaults: command not found
$ sudo lightdm-set-defaults
sudo: lightdm-set-defaults: command not found
$ lightdm -v
lightdm 1.4.0

synaptic 0.75.12 'Quick filter' finds no matches on 'lightdm-set-defaults'.

How do I install 'lightdm-set-defaults'?

  • I experience the issue where the command isn't installed. Are you running Ubuntu 13.04 Raring Ringtail or a close variant? I am, and the lightdm-set-defaults functionality is gone. Perhaps it's an issue that will be resolved prior to the final release in April? – user141525 Mar 19 '13 at 1:12
  • lightdm-set-defaults is probably not on your PATH Try: sudo /usr/lib/lightdm/lightdm-set-defaults – coldeq Apr 21 '13 at 21:12
  • @coldeq make that an answer. – CW Holeman II May 9 '13 at 20:24
  • No, it's not even on the path, as of Ubuntu 14.04. I think Ostermiller's answer is correct. No longer available. The problem is, when you edit the configuration file, you have to restart lightdm, which is a very heavyweight and destructive operation. It would be nice if there were a way to update the configuration without disturbing current runtime state, either by using an external command or by having lightdm monitor the configuration file for changes. – BobDoolittle Sep 12 '14 at 15:00

As of Ubuntu Trusy 14.04, lightdm-set-defaults is no longer available. This is because lightdm now uses a configuration directory /etc/lightdm/lightdm.conf.d/ rather than a single configuration file. The files in this directory can be edited by hand, new files can be added, or files can be removed. There is no longer any need for a command that edits the single configuration file.

  • so how can i set values in /etc/lightdm/lightdm.conf.d/ to defaults? – neckTwi May 25 '14 at 15:26
  • To restore all the lightdm configuration files to their default value, see the answer on this question: askubuntu.com/questions/66533/… – Stephen Ostermiller May 25 '14 at 17:11
  • I disagree with "no longer any need", since when you update the configuration file you must restart lightdm. See my comment on the Q above. – BobDoolittle Sep 12 '14 at 15:07
  • 1
    To my knowledge, lightdm-set-defaults just edited the configuration files and did not cause any changes to the running instance of lightdm. Even with that command, you still would have had to restart lightdm for your changes to take effect. – Stephen Ostermiller Sep 12 '14 at 16:06

As you can see by searching the packages.ubuntu.com website, it's a command, provided by the lightdm package, which you already have I assume.

So, just run in a terminal:

sudo lightdm-set-defaults
  • Not true, at least as of Ubuntu 14.04. – BobDoolittle Sep 12 '14 at 15:01
  • @BobDoolittle You're right. Removed in 14.04 it appears. – gertvdijk Sep 12 '14 at 15:04

The command is not in the path so you need to run it using the full name, i.e.:


The Wiki page is incorrect - you can edit the configuration if you want, the purpose of lightdm-set-defaults is so scripts can easily modify the configuration.

  • 2
    This must have been true at the time Robert wrote it, since he's the man for LightDM. But it does not appear to be true any more as of Ubuntu 14.04. I don't have that command on my system, and apt-file search doesn't turn anything up. – BobDoolittle Sep 12 '14 at 15:03

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