code: function copyFiles(srcfile, dstfile, callback) {
          var fs = require("fs");
          var rs = fs.createReadStream(srcfile);
          var ws = fs.createWriteStream(dstfile);
          rs.on("data", function(d) {
              ws.write(d);
          });
          rs.on("end", function() {
              ws.end();
              callback(true);
          });
      }
docs: Copy file1 to file2