|this works, but not technically "concurrant". As IVO said, batch can't do that.|
@echo off & setlocal enabledelayedexpansion
set /a sk=0
for /f "tokens=*" %%a in (d1.txt) do (
if !sk! equ 0 (set skip="tokens=*") else set skip="skip=!sk! tokens=*"
call :10 !sk!
set /a sk+=1
for /f %skip% %%b in (d2.txt) do echo %%b & goto :eof
if the data remains static, you might be better off to run this
batch as a "pre-formatter" to generate the interleaved data into
a temporary file then access that using the conventional method. The larger file#2 is, the slower the script will run.