Demon

@echo off
setlocal enabledelayedexpansion
set /a n = 0
(for /f %%i in (ip.txt) do (
    set /a n = n + 1
    if !n! geq 3 (
        echo ;%%i
    ) else (
        echo %%i
    )
)) > 1.txt
pause
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CrLf

sed "3,$s/.*/;&/" 1.txt
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sed "1,2s/^;//" 1.txt
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