Allow "unknown sources" from Terminal without going to Settings App?

I have a corrupted Settings app in CyanogenMod and have a possible idea to restore a backup of it (App and Data) in Titanium Backup. But it's currently set to not allow "unknown sources" so Titanium cannot actually restore the old Settings over the current (corrupted) one. I have a Terminal app installed on the phone. Is there a command in Terminal to essentially 'tick' that "unknown sources" setting, since I can't open the Settings app itself? (It gives this .)