siegeSig

siegeSig is my online signature for websites, message boards, mailing lists, etc...

This is it:

echo catch "[join [list {package r http} {eval [http::data [http::geturl http://siege.org]]}] {; }]" | wish

On it's own, that isn't a very interesting little snippit. Anyone with scripting (computer scripting) experience will be able to ID this pretty quickly as a small computer program. Most people, even if they don't understand the language it is written in, will probably understand the function. Probably no one would ever actually run it. Especially if they're one of the ones that understands its function.

siegeSig is just over 100 characters. It's a small program designed to download a much larger program from the internet and run it. But that's not the interesting part. The interesting thing is that this very same line of code will work on practically any computer. Windows, Mac OS X, Unix, Linux, etc... It should work just about anywhere, provided the two prerequisites are available: 1) A graphical environment (common to most modern desktops), and 2) the 'wish' program is needed. Wish is one of the the executable names used by the Tcl/Tk programming language. siegeSig is a Tcl script. And it's a highly portable one at that.

As it happens, the second half of siegeSig (the part that gets downloaded) is the interesting part. What exactly it does is not really important (you'll have to risk running the command to see), at least not so much so as how it does what it does. How do just over 100 characters, one single line of code, yeild the end result that they do? The magic is pretty much smack in the middle of the siegeSig command... it's the "eval" statment wrapped around what is essentially an HTTP GET request. This script literally says "go get the contents of http://siege.us and run it as a script."

And now that you're all back (don't think I don't know you all ran right over to siege.us), you see there's nothing more at siege.us than the same command you've seen before. "Black Magic," you scream! Well, in truth, a little. siege.us will only reveal the real source of siegeSig to those using the correct command. How? Well, this isn't a lecture on HTTP now is it?

Of course, nothing works without fail. Certain things (like firewalls) can get in the way of siegeSig working properly. That's not to say you can't use a proxy (and should if you need to), but adding a statment to do so makes my wee little signature a bit longer and more cumbersome. I suggest you go learn Tcl if you want to try it.