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From what I've red I'm legally allowed to modify my personal copy of Ubuntu. Correct me if I am wrong here though.

So my question: I would like to edit how the user logs in. I am using the default 13.10 lightdm. I could not find the login/password text box processing part within lightdm though.

To elaborate on what I am trying to achieve: Take for example that I try to log in as a user 'TEST'. The password for this user is 'MyTestPassword'. I would like to do something when the user enters foe example 'HINT'. As you see, this is not about the appearance of the login screen.

I would appreciate if someone could point me in the direction of the files/ source code that has to be modified.

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What do you want to happen when they enter "HINT". – wojox Feb 24 '14 at 19:44
up vote 0 down vote accepted

LightDM is free software, so you are allowed to make any changes you wish and even distribute them if you want.

LightDM uses so called "greeters" to display the login screen. There are several greeters available.

By default Ubuntu uses the unity-greeter. You can get its source code using

apt-get source unity-greeter

or from

If you have some web design skills it may worth to have a look at "webkit-greeter" (package lightdm-webkit-greeter). This greeter lets you use a HTML file as login screen using JavaScript to interface with LightDM.

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Thank you, will check this out and report whether my problem is solved. – LizardMaster Feb 25 '14 at 20:55
This appears to be a valid approach, harder than I thought but for anyone else, look at "src/greeter-list.vala". – LizardMaster Feb 27 '14 at 22:48

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