[greg zakharov]

Код:

@echo off
  setlocal
    set "i=0"
    for %%i in (%*) do set /a "i+=1"
    if "%i%" equ "1" if "%i%" equ "/?" goto:man
    if "%i%" neq "1" goto:man
    
    set "ext=%1"
    if "%ext:~0,1%" neq "." set "ext=.%ext%"
    for /f "skip=3 tokens=2,*" %%i in (
      '2^>nul reg query "HKCR\%ext%" /ve'
    ) do (
      for /f "tokens=4 delims=\" %%k in (
        'reg query "HKCR\%%j\shell"'
      ) do (
        for /f "skip=3 tokens=2,*" %%l in (
          'reg query "HKCR\%%j\shell\%%k\command" /ve'
        ) do echo:%%k: %%m
      )
    )
  endlocal
exit /b

:man
  for %%i in (
    "Usage: %~n0 <extension>"
    ""
    ".e.g.: C:\>%~n0 txt"
    ".e.g.: C:\>%~n0 .txt"
    "Output:"
    "   open: %%SystemRoot%%\system32\NOTEPAD.EXE %%1"
    "   print: %%SystemRoot%%\system32\NOTEPAD.EXE /p %%1"
    "   printto: %%SystemRoot%%\system32\notepad.exe /pt "%%1" "%%2" "%%3" "%%4""
  ) do echo:%%~i
exit /b