Under Ubuntu most software is available in Ubuntu repositories. What happens if I install a newer version of software from different ppa that is not available in repositories yet?
Will it upgrade the old version to the new one? In this case I have no fallback if the new version is faulty. What happens if Ubuntu repositories publishes an update itself later?
Will it install a second (new-)version in parallel? If this is the case how do I control which version I launch when I type in the program name on command line?
(To be specific: The software "Arduino 1.06" is offered via Ubuntu repositories. There is a new version 1.6 available, but not in the Ubuntu repositories yet. What happens to my old version when I install 1.6?)