AutoIt, Apple Script, what about Linux?
 

Windows has AutoIt, Mac has AppleScript, but what is the auto scripting language for Linux? I would naturally assume Bash but can't you use Bash, or a similar scripting/command language, in DOS?

...cron?

Linux has no one scripting language. Bash, fish, scsh, Python, Perl and Ruby are just a few programming languages that can be used for automation, but strictly speaking, any language can potentially achieve the same. It's just a case of running the correct programs, or accessing the correct interfaces, such as KDE's DCOP service. Almost everything in Linux can be automated.

I'm not sure what you mean by the second statement. DOS is an operating system with a built in command line similar to Bash, but lacking many of the features. In any version of Windows after '95, you'll find that DOS itself has been phased out, but the command line interface remains. Microsoft don't have much of an interest in improving it, however, so it's still rather primative compared to the shells under Linux.

You can get Bash to run under Windows via Cygwin, however.

Now that's not completely true. Have you not heard of MSH codename Monad?

I'd use Bash or Perl in *nix, you can find those installed on almost any distro.

Python is about as ubiquitous as Perl, and much nicer IMHO.

KDE4 will make heavy use of EMCAScript.