I've installed Scala IDE for Eclipse using the update mechanism, and then I found that there's no command line tools included there. So is it correct that I should download another copy of Scala package for the command line support and maintain both separately?
Or is there an integrated way to get it work in both environments? I just want to write and debug code in Eclipse and occasionally run it on the command line.
First, you can open a Scala command-line within Eclipse. Just go to Window -> Show View -> Scala Interpreter, and it will open an interpreter window that has your project loaded into the classpath.
Second, there's nothing wrong with having a separate Scala installation for command-line use. I do this. It's often convenient to have a few terminal windows where you can run stuff or quickly test bits of code.