Create unique file name Windows batch

Question

I have seen many posts about creating a unique filename from the naive %TIME% to the plausible (but insufficient) %RANDOM%. Using wmic os get localdatetime is m

Answer 1

You could use certutil to base64 encode %date% %time% with a %random% seed like this:

@echo off
setlocal

:: generate unique ID string
>"%temp%\~%~n0.%username%.a" echo %username%%date%%time%%random%
>NUL certutil -encode "%temp%\~%~n0.%username%.a" "%temp%\~%~n0.%username%.b"
for /f "usebackq EOL=- delims==" %%I in ("%temp%\~%~n0.%username%.b") do set "unique_id=%%I"
del "%temp%\~%~n0.%username%.a" "%temp%\~%~n0.%username%.b"

echo %unique_id%

In case the same script is being run from the same directory by multiple users, I added %username% to the temp files to avoid further conflict. I suppose you could replace %random% with %username% for the same effect. Then you'd only get a conflict if a single user executes the same code block twice concurrently.

(Edit: added %username% as a seed for uniqueness.)