detach.js

detach.js

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

// spawn_detached(file, [args = []], [options = {}], [callback]);
function spawn_detached(file, args, options, callback) {
  if (arguments.length == 2 &&
      typeof args == 'function') {
    callback = arguments[1];
    args = undefined;
  }
  if (arguments.length == 3 && 
      typeof options == 'function') {
    callback = arguments[2];
    options = undefined;
  }

  // Convert `file` and `args` into a string that can be run on the command line.
  var shell_cmd = [file].concat(args || []).map(function(arg) {
    if (!arg || /[\s\r\n\0\\"]/.test(arg)) {
      arg = arg.replace(/[\r\n\0\\"]/g, function(m) {
        return '\\' + m;
      });
      arg = '"' + arg + '"';
    }
    return arg;
  }).join(' ');
  
  // Build arguments for sh
  var shell_args = [ '-c', 'setsid',
                     '&&', shell_cmd, '</dev/null', '>/dev/null', '2>&1' ];

  var cp = spawn('sh', shell_args, options);
  
  if (callback) {
    var output = "";
    cp.stdout.setEncoding('utf8');
    cp.stderr.setEncoding('utf8');
    cp.stdout.on('data', onOutput);
    cp.stderr.on('data', onOutput);

    // In node 0.7 the event we're interested in got renamed from 'exit' to 'end'.
    if (/^0\.(2|4|6)\./.test(process.versions.node)) {
      cp.on('exit', onEnd);
    } else {
      cp.on('end', onEnd);
    }
      
    function onOutput(s) {
      if (output.length < 10240)
        output += s;
    }

    function onEnd(exitCode, termSignal) {
      callback(exitCode, termSignal, output);
    } 
  }
}

spawn_detached("/usr/root/hello world", ['I"m', 'The walrus', 'backslash\\', '', 'hi2']);