The unique feature of Firefox is to create many profiles which contains book maks, home page, tool bar......
When I use selenium to run test suite in terminal, some persons suggest that we need to specify -firefoxProfileTemplate(that is the location of profile to be used).
The link below will tell us what is profile for FF, and how to create it, use it, delete it and move it from on machine to another.
To manage profiles, we need to close FF, and in terminal, type firefox ProfileManager, then a dialogue pops up.