The "-cp" option of groovy is the same with Java.
Wildcards can be used on JDK6 or later. For example:
groovy -cp "/home/chad/apps/http-builder-0.6/:/home/chad/apps/http-builder-0.6/dependencies/" httpex.groovy
Note1: "**" is not supported, which means above command can not written as:
groovy -cp "/home/chad/apps/http-builder-0.6/**" httpex.groovy
Note2: ".jar" is not supported, which means "/home/chad/apps/http-builder-0.6/.jar" is invalid;
Note3: the double quotes of classpath is necessary;
Note4: "/home/chad" in classpath can not be replaced by "~";
See: http://stackoverflow.com/questions/219585/setting-multiple-jars-in-java-classpath