install.js

var os = require('os');
var child_process = require('child_process');
var fs = require('fs');

fs.copy = function (src, dest, callBach) {
    fs.open(src, 'r', function (err, rfd) {
        fs.open(dest, 'w+', function (err, wfd) {
            var srcStream = fs.createReadStream(null, { fd: rfd });
            var destStream = fs.createWriteStream(null, { fd: wfd });
            srcStream.pipe(destStream);
            srcStream.on('close', function () {
                callBach();
            });
        });
    });
};

var run_installer = function () {
    child_process.exec('(node-gyp rebuild) || (exit 0)', function (err, stdout, stderr) {
        console.log(stdout);
        console.log(stderr);
        if (stderr.indexOf('gyp ERR!') > -1) {
            console.log('Failed to compile ntrujs for your platform. To ensure successful compilation; please make sure that your platform-specific NTRU libraries are in the lib/lib folder. If you have downloaded pre-compiled binaries and do not wish to modify them, you can safely ignore this error.');
            process.exit(0);
        } else {
            fs.copy('build/Release/addon.node', 'lib/addon-'+os.platform()+'-'+os.arch()+'.node', function () {
                process.exit(0);
            });
        }
    });
};

var src_gyp = "binding_linux.gyp";

switch(os.platform()) {
  case "win32": src_gyp = "windows.gysrc"; break;
  case "darwin": src_gyp = "darwin.gysrc"; break;
  default: src_gyp = "linux.gysrc"; break;
}

console.log('Source .gyp file: ' + src_gyp);
fs.copy(src_gyp, 'binding.gyp', function () {
    run_installer();
});