Генерировать большой файл заполненный определенными случайными символами?

>test.txt (for /l %%# in (1 1 10000) do @echo:1 b d d1)

echo 1bd>1.txt
for /L %%i in (1,1,8) do (
copy 1.txt+1.txt+1.txt 2.txt /b
copy 2.txt+2.txt+2.txt 1.txt /b
)

echo 1bd>1.txt
for /L %%i in (1,1,8) do (
copy 1.txt+1.txt+1.txt 2.txt /b
copy 2.txt+2.txt+2.txt 1.txt /b
)

powershell $name='c:\tmp\tmp.txt'; $fs = New-Object IO.FileStream($Name,[IO.FileMode]::Open,[Security.AccessControl.FileSystemRights]::AppendData,[IO.FileShare]::Read,8,[IO.FileOptions]::None);$TextBytes = [Text.Encoding]::GetEncoding('windows-1251').GetBytes('1bd');for ($i = 0; $i -lt 5; $i++) {$fs.Write($TextBytes,0,$TextBytes.Count)};$fs.Close()

@echo off
SetLocal EnableExtensions EnableDelayedExpansion
set min=-50
set max=50
set n=10
set file=numbers.txt
for /L %%C in (1,1,%n%) do (
  set /a i=!random!%%^(max-min+1^)+min
  <nul set /p "x=!i! ">> "%file%"
)

echo|set/p=1bd>1.txt
for /L %%i in (1,1,4) do (
copy 1.txt /b +1.txt /b +1.txt /b 2.txt
copy 2.txt /b +2.txt /b +2.txt /b 1.txt
)

@echo off
set min=1
set max=3
set var1=1
set var2=b
set var3=d
setlocal enabledelayedexpansion
for /l %%a in (1,1,1000) do (
    call :1
)
echo.
pause
exit /b
 
:1
set /a n=%random%%%(max-min+1)+min
<nul set /p  a=!var%n%!
exit /b

@echo off
set min=1
set max=3
set var1=1
set var2=b
set var3=d
setlocal enabledelayedexpansion
for /l %%a in (1,1,1000) do (
    call :1
)
echo.
pause
exit /b
 
:1
set /a n=%random%%%(max-min+1)+min
<nul set /p  a=!var%n%!
exit /b

::echo|set/p=1bd>1.txt
setlocal EnableDelayedExpansion
Set _Alphanumeric=abcdfghijklmnpqrstuvwxyz0123456789
set rnd=0
:loop
  set/a rnd=(17*!rnd!+!random!) %% 481899 %% 35
  echo|set/p=!_Alphanumeric:~%rnd%,1!>>1.txt
  set/a j+=1
  if !j! GEQ 1500 exit
goto loop

@echo off
set min=1
set max=3
set var1=1
set var2=b
set var3=d
setlocal enabledelayedexpansion
(
for /l %%a in (1,1,1000) do (
    call :1
)
)>out.txt
echo.
pause
exit /b
 
:1
set /a n=%random%%%(max-min+1)+min
<nul set /p  a=!var%n%!
exit /b

::echo|set/p=1bd>1.txt
setlocal EnableDelayedExpansion
Set _Alphanumeric=abcdfghijklmnpqrstuvwxyz0123456789
set rnd=0
:loop
  set/a rnd=(17*!rnd!+!random!) %% 481899 %% 35
  echo|set/p=!_Alphanumeric:~%rnd%,1!>>1.txt
  set/a j+=1
  if !j! GEQ 1500 exit
goto loop

setlocal EnableDelayedExpansion
::_Alphanumeric строка необходимых символов
Set _Alphanumeric=abcdfghijklmnpqrstuvwxyz0123456789
set rnd=0
echo.яю>$end.tmp
::последнее число в ур-е rnd указывает кол-во символов +1
:loop
  set/a rnd=(17*!rnd!+!random!) %% 481899 %% 35
  echo|set/p=!_Alphanumeric:~%rnd%,1!>>$.tmp
  set/a j+=1
  if !j! GEQ 1000 copy $.tmp +$end.tmp 1.txt & exit
goto loop

set data=!data!!rnd!

echo|set/p=1bd>1.txt