Question

I’m using mongoDB on an ubuntu server. However I’m using a javascript to store data and do some map/reduce. I would like to measure these operations and write the results into a file. Somehow I fail to open a file and write into it.. I tried the following:

f = new File("myfile.txt");
if(f.open("w") == true)
{   
    f.write("test");
 f.Close();
}

Answer 1

The file object within spidermonkey (the JS engine MongoDB uses, and coincidently the console) has been made obsolete: https://developer.mozilla.org/en-US/docs/SpiderMonkey/File_object . Not only that but it wasn’t standard to spidermonkey anyway so that was a long shot.

As @gkamal states, the best way is to pipe the output of the MongoDB console like so:

mongo someprocess.js > outpout