Excuse me for butting in with an off-topic question.
Is there a downside to using su -, instead of su?
Perhaps a few minor annoyances.
For instance: when you run "su" your current directory remains your current directory; but after running "su -" your current directory always becomes /root. So if you want to run a command on a file in what used to be your current directory, you have to specify the path to it, or cd back to it.
Note that if you su to root and a program needs root's envirenment, you don't have to exit and start again with "su -" and root's password; just type "su -" as root and you'll get the whole environment.
I never use su - unless I am following someone's advice.
My concern is that the results of certain commands from root environment could cause an ownership issue later on.
But I am a dummy.
If you create a file or a folder as root that file or folder will be owned by root regardless of whether you've run "su" or "su -" to become root.