I use these scripts to test my Grails plugins.
They should run on any *nix system, but I've tested them only on OSX. They use the following standard programs: bash, perl, and sed. They also require the gvmtool for switching between Grails versions.
When finished, the script will start your browser with an appropriate page showing either the geb test results page for a single test or showing a summary page with links to the individual geb tests if the 'all' argument is given.