@echo off
setlocal enabledelayedexpansion
for /f "delims=" %%a in ('type 11.txt') do (
set /a m+=1
set "home!m!=%%a"
)
for /f "delims=" %%b in ('type 12.txt') do (
set /a n+=1
set "bat!n!=%%b"
)
if %m% gtr %n% (
for /l %%c in (1 1 %m%) do (
if not "!home%%c!"=="" echo !home%%c!
if not "!bat%%c!"=="" echo !bat%%c!
)
) else (
for /l %%d in (1 1 %n%) do (
if not "!home%%d!"=="" echo !home%%d!
if not "!bat%%d!"=="" echo !bat%%d!
)
)
pause

@echo off
for /f "delims=" %%i in (1.txt) do set /a n+=1&call,set "_%%n%%=%%i"
for /f "delims=" %%i in (2.txt) do set /a m+=1&call,set ".%%m%%=%%i"
if %n% gtr %m% (set "num=%n%") else (set "num=%m%")
for /l %%i in (1,1,%num%) do (
if defined _%%i call,echo %%_%%i%%
if defined .%%i call,echo %%.%%i%%
)
pause>nul

@echo off&setlocal enabledelayedexpansion&set n=-1
for /f "delims=" %%a in (1.txt) do (
set/a n+=1
set flag=
call :lp %%a
if not defined flag echo %%a
)
:lp
if "%1" equ "" set/a n+=1
set m=skip=%n%
if "%m%" equ "skip=0" set "m="
for /f "%m% delims=" %%a in (2.txt) do if "%1" neq "" (echo %1&echo %%a&set flag=a&goto :eof) else echo %%a
if "%1" equ "" pause

@echo off
set "n=-1"&set "flag=a"
:begin
set /a n+=1
if %n% equ 0 (set "m=") else (set "m=skip=%n%")
for /f "%m% delims=" %%i in (1.txt) do echo %%i&if defined flag goto next
set no=a
:next
for /f "%m% delims=" %%i in (2.txt) do echo %%i&goto begin
if not defined no set "flag="&goto begin
pause>nul

@echo off&setlocal enabledelayedexpansion
set "num=0"
for %%a in (1.txt 2.txt) do (
for /f "delims=" %%i in (%%a) do (
set /a n+=1
if !n! gtr !num! set "num=!n!"
set /p=%%i <nul>>temp.txt
)
echo.>>temp.txt&set "n=0"
)
:lp
set /a n+=1
for /f "tokens=%n%" %%i in (temp.txt) do echo %%i
if %n% neq %num% goto lp
del /q temp.txt&pause>nul