如何在指定字符串后通过CMD向文件中添加一行？

line 1
line 2
line 3

@echo off
setlocal enabledelayedexpansion

set "search=line 2"
set "newline=new line"
set "tempfile=temp.txt"

(for /f "tokens=*" %%A in (example.txt) do (
    echo %%A
    if "%%A"=="%search%" echo %newline%
)) > %tempfile%

move /y %tempfile% example.txt

powershell -Command "& {
    $filePath = 'example.txt';
    $search = 'line 2';
    $newLine = 'new line';
    $content = Get-Content $filePath;
    $newContent = @();
    foreach ($line in $content) {
        $newContent += $line;
        if ($line -eq $search) {
            $newContent += $newLine;
        }
    }
    $newContent | Set-Content $filePath;
}"

sed '/line 2/a new line' example.txt > temp.txt && mv temp.txt example.txt

awk '{print} /line 2/ {print "new line"}' example.txt > temp.txt && mv temp.txt example.txt