Simple command line utility in node

node-sample-commandline.js

var fs = require('fs');
function parseArg(opt) {
    var args = Array.prototype.slice.call(process.argv, 2);

    var matches = args.filter(function(arg) {
        return arg.indexOf(opt) > -1;
    });

    if (Array.isArray(matches) && matches.length) {
        return matches[0].split('=')[1];
    }
}

function main(dirpath) {
    var usageDie = function(msg) {
        console.error("error: " + msg);
        console.error();
        console.error("usage: " + process.argv[0] + " --path=dirpath");
        console.error();
        console.error("    --path=dirpath\t- Path of the directory");
        console.error("    --help\t- Help");
        process.exit(1);
    };

    dirpath = dirpath || parseArg('--path', '.');
    if (!dirpath) usageDie('invalid directory path');

    fs.readdir(dirpath, function(err, items) {
        if (err) {
          console.error(err);
          return;
        }
        for (var i=0; i<items.length; i++) {
            console.log(items[i]);
        }
    });

    return;
}

if (require.main === module) {
    main();
}

module.exports = main;