Javascript：替换.txt文件中的最后一行

Question

I wish to open a file and replace the last line. Not the empty last line, the last last with text, forexample;

Line1
Line2
Line3

I would like to transform this into

Line1
Line2
Last Line

Answer 1

With Windows Scripting Host:

var fso = new ActiveXObject("Scripting.FileSystemObject");

var fh = fso.OpenTextFile("test.txt");
var lines = fh.ReadAll();
fh.Close();

lines = lines.split('\r\n');
lines = lines.slice(0, -2);
lines.push('Last Line');
lines = lines.join('\r\n');

var fh = fso.CreateTextFile("test.txt", true);
fh.Write(lines);
fh.Close();