Convert long filename to short filename (8.3) using cmd.exe

Question

I am trying to convert a long filename to a short filename (8.3) on Windows.

A batch-file with a command line argument works as intended:

short.bat:

Answer 1

Replace the filename.txt to the filename you want to convert to 8.3

dir /x filename.txt

You will then have to split the result with whitespace as your delimiter (\s in regex). Then the value with the ~ is your short filename. If your filename is short to begin with, then you won't find a string containing a ~.

Answer 2

cmd /c for %A in ("C:\Documents and Settings\User\NTUSER.DAT") do @echo %~sA

Answer 3

Here is an example that read in the registry the location of your "appdata\local" folder and convert it to short path:

cls
@echo off
cd /d "%~dp0"
chcp 65001 >nul

for /f "skip=1" %%a in ('"wmic useraccount where name='%USERNAME%' get sid"') do (
    for %%b in (%%a) do set current_SID=%%b
)
set current_username=%USERNAME%
set current_userprofile=%USERPROFILE%

set key_to_read=HKEY_USERS\%current_SID%\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
set value_to_read=Local AppData
rem If value_to_read contains ? space(s) set tokens to 2+?
for /f "usebackq eol= tokens=3,* delims= " %%a in (`reg query "%key_to_read%" /v "%value_to_read%" 2^>nul ^| find "%value_to_read%"`) do (
    set value_type=%%a
    set data_read=%%b
)
set data_read=%data_read:USERPROFILE=current_userprofile%
call set "data_read=%data_read%"
set current_local_appdata=%data_read%

set current_local_appdata_temp=%current_local_appdata%\Temp
echo %current_local_appdata_temp%

for %%a in ("%current_local_appdata_temp%") do set "current_local_appdata_temp_short=%%~sa"
echo %current_local_appdata_temp_short%

pause
exit