This Node module takes care of most of the routine parts of importing a file into a MongoDB collection, so long as each record is on its own line. It also handles parsing command line parameters.

Example:

#!/usr/bin/env node
var lomi = require('line-oriented-mongo-importer');

function processLine(lineInfo) {
    // This method will be called once for each line in the file(s). The return value is
    // inserted into the MongoDB collection. lineInfo has the following structure:
    // {
    //     text: 'your,data', // the line that was read from the file
    //     filename: 'data.csv', // the name of the file that text came from (or the id assigned to stdin)
    //     lineNumber: 42, // the line number of the file that was passed in
    //     recordId: 'data.csv-42' // a suggested value for _id that will be reproducible if
    //                             // this file is imported again
    // }


    if (/*some error condition*/) {
        return null; // this will cause no document to be inserted for this line
    }
    var doc = { /* create the document from lineInfo.text */};
    return doc;
}

lomi.process(process.argv, process.stdin, processLine, function() {
    console.log("Finished parsing");
    process.exit(0);
});