code: function fallback(){
      exec("echo %OPENCV_DIR%", function(error, stdout, stderr){
          stdout = cleanupEchoOutput(stdout);
          if(error){
              throw new Error("ERROR: There was an error reading OPENCV_DIR");
          }
          else if(stdout === "%OPENCV_DIR%") {
              throw new Error("ERROR: OPENCV_DIR doesn't seem to be defined");
          }
          else {
              printPaths(stdout);
          }
      });
  }
docs: ======================Windows Specific=======================================