Hi -
We'd need more information to answer your question.
In general, "interactive" means you're directly interacting with the computer, vs "non-interactive", "scripted", or "batch" modes, which mean you tell the computer to do something, and then go away while it does it.
As OS can have any number of different "shells". For example, the default command-line shell in Linux is "bash" ... but people often interact with the system via a GUI desktop like KDE or Gnome. These GUI desktops can also be considered "shells".
The Linux bash shell lends itself extremely well to both "interactive" mode (typing in commands in a terminal window) and "batch" mode (writing simple .. or quite elaborate ... shell scripts to automate work).
'Hope that helps .. PSM
PS:
Here's a Wikipedia article that might help clarify a bit further:
http://en.wikipedia.org/wiki/Unix_shell