Node.js readline 逐行读取、写入文件内容的示例

var readline = require('readline'); var fs = require('fs'); var os = require('os'); var fReadName = './1.log'; var fWriteName = './1.readline.log'; var fRead = fs.createReadStream(fReadName); var fWrite = fs.createWriteStream(fWriteName); var objReadline = readline.createInterface({  input: fRead, // 这是另一种复制方式，这样on('line')里就不必再调用fWrite.write(line)，当只是纯粹复制文件时推荐使用 // 但文件末尾会多算一次index计数 sodino.com // output: fWrite, // terminal: true });   var index = 1; objReadline.on('line', (line)=>{  var tmp = 'line' + index.toString() + ':' + line;  fWrite.write(tmp + os.EOL); // 下一行  console.log(index, line);  index ++; });  objReadline.on('close', ()=>{  console.log('readline close...'); }); 

var readline = require('readline'); var fs = require('fs'); var os = require('os');  var fReadName = './1.log'; var fWriteName = './1.readline.log'; var fRead = fs.createReadStream(fReadName); var fWrite = fs.createWriteStream(fWriteName);  var enableWriteIndex = true; fRead.on('end', ()=>{  console.log('end');  enableWriteIndex = false; });  var objReadline = readline.createInterface({  input: fRead,  output: fWrite,  terminal: true });  var index = 1; fWrite.write('line' + index.toString() +':'); objReadline.on('line', (line)=>{  console.log(index, line);  if (enableWriteIndex) {  // 由于readline::output是先写入后调用的on('line')事件，  // 所以已经读取文件完毕时就不需要再写行号了... sodino.com  index ++;  var tmp = 'line' + index.toString() + ':';  fWrite.write(tmp);  } }); objReadline.on('close', ()=>{  console.log('readline close...'); });