A little trial and error, and a lot of scanning man, info and by-example Web pages later, I have:

Turns out it will pretty much comply with whatever your shell allows. You just have to format your strings according to the shell's syntax. If you happen to use a punctuation mark that your shell (eg bash) understands intuitively as a command (ye old bang <!> comes racing to mind), and you know how to isolate it/them so they're taken to be part of the string instead of as command shorthand, then this iptc tagger will glom onto that and use it as intended.

So after just now taken three sentences to say what could have been said in just one I'll try to hunt down the link for downloading it and add it to an edit of this post sometime in the next 48hrs. Barring anything going wrong with my hardware, OS or net-access account.

BZT