Write batch variable into specific line in a text file

I have a batch file where I need to write a variable into a specific line of a text file and override what is all ready in that line. I have the code to read specific lines from the file maybe I could switch it around to also write?

Reading lines code:

setLocal EnableDelayedExpansion
for /f "tokens=* delims= " %%a in (variables.txt) do (
set /a N+=1
set v!N!=%%a
)
set variable1=!v1!
set variable2=!v2!
set variable3=!v3!
set variable4=!v4!

I've tried to add echo %variable1% > !v4! something like that but it doesn't work.

I figured it out!! Here is the code for anyone else who might ever need it.

@echo off
setlocal enableextensions enabledelayedexpansion

set inputfile=variables.txt

set tempfile=%random%-%random%.tmp

copy /y nul %tempfile%

set line=0

for /f "delims=" %%l in (%inputfile%) do (
    set /a line+=1
    if !line!==4 (
        echo WORDS YOU REPLACE IT WITH>>%tempfile%
    ) else (
        echo %%l>>%tempfile%
    )
)

del %inputfile%
ren %tempfile% %inputfile%

endlocal