I want to execute csv files result from joined each file inside one folder with batch script. Before I try with nested loop and show all rows, it’s work. But I want to add some logic to process all rows with adjust each header/column when loops is processing. This is how I show all rows with nested loop and joined each csv files:

for /f "usebackq delims=|" %%f in (`dir /b "C:Usersmyfolder*.csv"`) do (
    for /f "usebackq tokens=* delims=," %%i in (%%f) do (
        echo %%i >>joinedfiles.csv
    )
)

Only add other logic, I try to separate each line with header:

set "oldFileHeader=NO,NO ANTRIAN,NO SPAJ,TIPE DOKUMEN,TGL KIRIM,KEY"
set "newFileHeader=No Urut,BOX_NO,NoAntrian,NoPolis,Jenis Dokumen,Jenis Transaksi,Tgl Penerimaan,NoAntrian NB,Tgl Penerimaan NB,Key"

for /f "usebackq delims=|" %%f in (`dir /b "C:Usersmyfolder*.csv"`) do (
    for /f "usebackq tokens=* delims=," %%i in (%%f) do (
        set /a count+=1
        set "line=%%i"
        
        if "!line!" EQU "!newheader!" (
            set /a lineNumber=!count!-1
            for /f "usebackq tokens=* delims=," %%a in (%%i) do (
                echo %%a
            )
        )

        if "!line!" EQU "!oldheader!" (
            set /a lineNumber=!count!-1
            echo count: %lineNumber%

            for /f "skip=%lineNumber% usebackq tokens=1-6 delims=," %%a in (%%i) do (
                set first=%%a
                set second=%%b
                set third=%%c
                set fourth=%%d
                set fifth=%%e
                
                echo !first!,!second!,!third!,!fourth!,!fifth!
            )
        )
    )
)

Thats code above is not working because executed lines only header, not a each row based on header file.

My question is, how to executed thats file and separate based on header.