Waiting for Lion to show up in App Store? We are too. Here's how we are checking.
When you want to pull a URL from Mac App Store, you need to emulate its user agent. curl -silent -A "iMacAppStore/1.0.1 (Macintosh; U; Intel Mac OS X 10.6.7; en) AppleWebKit/533.20.25" will do that for you.
Want to search the store? Same idea, but give it a query like this: curl -A "iMacAppStore/1.0.1 (Macintosh; U; Intel Mac OS X 10.6.7; en) AppleWebKit/533.20.25" -H "X-Apple-Store-Front: 143441-1,13" 'http://ax.search.itunes.apple.com/WebObjects/MZSearch.woa/wa/search?q=SEARCH_PHRASE_HERE'
The search phrase must be URL-escaped, e.g. "OS X Lion" is "OS%20X%20Lion".
Then do a little grep-fu, namely grep -iv 'killer' | grep 'mt=12' | grep 'class=.name' These steps search for app listings only whose name does not include "killer", as in "Killer Guide for OS X Lion". Who knew?
I threw together a few utilities to help with this. Lionscanner is a command line app that performs this search (or, if you give it an argument searches for that instead of "OS X Lion") and then processes the results to kill everything but in-line text, i.e. no XML tags, following the greps I mentioned above.
If you run it without arguments it hunts for "OS X Lion". If it finds nothing, there's no "OS X Lion" product in App Store. Presumably. That's why I've also included the basic how-to. So you can create your own tools that are a little more flexible in case Apple doesn't name it quite "OS X Lion".
Second, I have my handy-dandy-age-of-the-dinosaurs-csh-script as always, the one you readers always mock me for. Still works, still csh, you still need to run it with something like repeat 5000 ./doLionCheck:
./lionscanner | grep -i "lion" > /dev/null
if ($? == 0) then
say "LION MAY BE AVAILABLE"
Okay, that's everything you need. Don't forget to make stuff executable (chmod 755). Now go forth and build some better tools for us.