Executes a command line process. Example:

 task stopTomcat(type:Exec) {
   workingDir '../tomcat/bin'

   //on windows:
   commandLine 'cmd', '/c', 'stop.bat'

   //on linux
   commandLine './stop.sh'

   //store the output instead of printing to the console:
   standardOutput = new ByteArrayOutputStream()

   //extension method stopTomcat.output() can be used to obtain the output:
   ext.output = {
     return standardOutput.toString()
   }
 }