@echo off
set ff=a.txt
set abc=a b c d e f g h i j k l m n o p q r s t u v w x y z
echo 稍候...
(for /f "delims=" %%i in ('type "%ff%"')do (
set h=%%i
for %%a in (%abc% .!')do set r=%%a&call :y
call set h=%%h:,=%%
call set h=%%h::=%%
call set h=%%h:"=%%
call echo.%%h%%))>temp.txt
move temp.txt "%ff%"
start "" "%ff%"
exit
:y
call set h=%%h:%r%=%%