Explain applescript vs terminal script vs shell scripts and Automator

Applescript is Apple's scripting language. Apple has also implemented an Open Scripting Architecture (OSA) that allows scripts to be called interchangeable within each other. I think there is more to it, but that's as much as I know. So, in shell script, you can call an Applescript, and in an Applescript, you can call a shell script.

The 'shell' is any of several unix shells that allow you to create interface with the OS to do tasks. Bash is one of those shells and is the default shell since Tiger, I think. The Terminal opens up a 'shell' within which you can run commands.

I can't offer any sources on unix shell programming, but I learned Applescript with two books:
+Danny Goodman's Applescript Handbook+ and +Applescript: The Definitive Guide+ by Matt Neuburg.

No. Applescript is an english like syntax.

tell application "Finder"
 if the (count of windows) is not 0 then
 set collapsed of every window to false
 end if
end tell

Google [unix shell scripts|http://www.google.com/search?client=safari&rls=en-us&q=unix shellscripts&ie=UTF-8&oe=UTF-8] and you can see several examples and tutorials.

I should have also pointed you to [Apple's Applescript Reference|http://www.apple.com/applescript>

Apple's goal was to bring programming to the rest of the world, but it is still not that easy. I'm pretty sure that's why Automator has evolved. It's like Applescript on steroids, but not quite polished, in my opinion.