批处理

有两个文本如下，实际中并不知道两文本各有多少行：

文本1.txt
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
ccccccccccccccccccccccccccccccccccccccc
eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
ggggggggggggggggggggggggggggggggggggggg
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

文本2.txt
hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj
nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn

要求用Windows下批处理和Linux下的shell脚本完成，两文本交替输出：
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
ccccccccccccccccccccccccccccccccccccccc
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj
ggggggggggggggggggggggggggggggggggggggg
nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

要求：
1 尽量不生成临时文件
2 代码要高效，代码尽量简洁
3 给出各种情况的测试结果截图（正常文件，巨大文件，一个空文件，两个空文件）
windows 下的代码为

@echo off

set "paths=1.txt"
for %%a in ("%paths%") do (
 if "%%~za" equ "0" (
   echo "1.txt empty"
   
    ) else (
    echo "1.txt not empty"
 )
)

set "paths=2.txt"
for %%a in ("%paths%") do (
 if "%%~za" equ "0" (
   echo "2.txt empty"
   pause
    ) else (
    echo "2.txt not empty"
 )
)


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

Linux下的代码为

paste txt1.txt txt2.txt | tr " " " "