I am soon going to have to migrate an entire computer lab (about 50 PCs) from Windows 7 to Ubuntu 14.04 LTS. As it's an university, 99% of the time (if not 100%) it will be used by students. There is not a central database of user accounts and credentials, so each PC will have only two accounts,
guest, with the latter configured to autologin (besides some customization as per this tutorial).
When the PCs are turned on, and the guest account logs in automaticcaly, the first thing shown after the window manager is loaded is this dialog box:
However, there's two problems:
- The very first person who sits at the computer at 9am will see the dialog box, click OK, use the PC, leave, not ending the session or locking the screen (because users), and the second user onwards won't see the message
- There is more relevant information that I'd like to convey for the lab users (lab rules, etc).
So, with this scenario in mind, what I want to achieve is having a dialog box really similar to this one (but with a different text, set by me) to popup whenever a computer isn't used for, say, 15 minutes. (For the purpose of this question, let's assume "not used" means no keyboard or mouse activity).
I have been directed to How does ubuntu determine inactivity before suspending? and How can a script detect a user's idle time? and use ruby or sheel scripts, but I don't know how to code.
Is there a simpler way to achieve what I need?