如何删除文件末尾的一行并将其放在文件顶部？

Question

这是我当前的代码：

const rl = require("readline");
const fs = require("fs");

const ri = rl.createInterface({
  input: fs.createReadStream("dot-error.log"),
  output: process.stdout,
  console: false,
});

ri.on("line", function (line: string) {
  const append: string = line.substring(line.indexOf("\n") + 1);   
});

我将如何创建一个 for 循环来抓取文件末尾的行并粘贴到文件的顶部并删除该行（在文件的末尾） ? 谢谢！

Answer 1

删除最后一行然后放在最前面

var fs = require("fs");

var lines = fs.readFileSync("dot-error.log", 'utf8'); // read the file
lines = lines.trim().split('\n'); // remove empty lines and split using \n
var lastLine = lines.pop() // get last line
lines.unshift(lastLine); // prepend last line
fs.writeFileSync("dot-error.log", lines.join('\n')); // write

编辑：颠倒顺序

var lines = fs.readFileSync("dot-error.log", 'utf8');
lines = lines.trim().split('\n');
lines.reverse();
fs.writeFileSync("dot-error.log", lines.join('\n'));

如何删除文件末尾的一行并将其放在文件顶部？

How do I delete a line at the end of the file and put it at the top of the file?

javascript

filesystems

fs

node.js