Ok, here's my solution to this:
1. Open Screensaver Preferences and ensure "Lock screen when screensaver is active" is checked.
2. Open up your text editor and paste the following into it:
- Code: Select all
3. Save the file somewhere safe, where it won't be accidentally deleted.
4. Right click the file you just created, go to Permissions and check the "Execute" box.
5. Open Startup Application Preferences and add an item pointing to the file you just created.
6. Enable auto-login.
This is a bit roundabout, and if someone could supply us with the command to lock the screen directly rather than using the screensaver it would be appreciated.
Edit - This also has the side effect that your screensaver will lock your computer now as well. I would assume that if you're looking to lock on boot then you don't mind this