code: function printHelp() {
          /* global slimer */
          var engine = phantom.casperEngine === 'slimerjs' ? slimer : phantom;
          var version = [engine.version.major, engine.version.minor, engine.version.patch].join('.');
          return __terminate([
              'CasperJS version ' + phantom.casperVersion.toString() +
              ' at ' + phantom.casperPath + ', using ' + phantom.casperEngine + ' version ' + version,
              fs.read(fs.pathJoin(phantom.casperPath, 'bin', 'usage.txt'))
          ].join('\n'));
      }
docs: Prints CasperJS help.