use spawn instead of exec to allow "real-time" feedback

[abh]

It'd be nice if there was an option to get each hop as traceroute finds them, rather than just a result when it's all done.

[jaw187]

abh, haven't been on GitHub in a while and never realized that there was a comment. Thanks for the suggestion! I'll look to rewrite it ASAP.

[abh]

for my application I wanted to use mtr instead of regular traceroute, I'm including the code I used below in case it's useful to you:

"use strict";

var spawn = require('child_process').spawn;

function trace(host, opts, cb) {
    if (!opts.cycles) { opts.cycles = 3; }
   var mtr = spawn('mtr', [ '--raw', '--report-cycles', opts.cycles, host ]);
   mtr.stderr.on('data', function (data) {
       console.error("ERROR: " + data);
   });
   mtr.stdout.on('data', function (data) {
       var lines = data.toString().split('\n');
       console.log("lines", lines);
       for (var i=0; i < lines.length; i++) {
           if (lines[i] === '') { break; }
           var r = lines[i].split(' ');
           r[1] = parseInt(r[1], 10);
           if (r[0] === 'p') {
               r[2] = parseInt(r[2], 10);
           }
           cb(null, r);
       }
   });
   mtr.on('exit', function(code) {
       console.log("mtr done!");
       cb(null, ["x", code]);
       if (code !== 0) {
           console.error('mtr process exited with code ' + code);
       }
   });
}

exports.trace_raw = function (host, opts, cb) {
    if (typeof opts === 'function') {
        cb = opts;
        opts = {};
    }
    trace(host, opts, cb);
};

[jaw187]

@abh Not sure if you're still interested or not, but I finally did as you suggested :) Latest code in master has it, but I've yet to publish version 2.0.0 to NPM