Hi Brian,
There are already two command line clients available: one that works
with Node.js and one that works with Rhino. We're a bit behind on
documenting these. If you're using Node.js and npm, you can do this to
install:
npm install -g csslint
Then you can run via:
csslint your.css another.css
If you'd like to use Rhino, go and download the latest JAR file from
http://www.mozilla.org/rhino/. In the CSS lint build directory,
there's a file called csslint-rhino.js. Grab that, and then you can
run this on the command line:
java -jar rhino.jar csslint-rhino.js your.css another.css
Hope this helps.
-N