How to set a variable for the current OS session only

Question

setx permanently modifies environment variables.
set only makes variables available during batch script duration.
Is there any way to set a

Answer 1

@ECHO Off
IF NOT EXIST q25244121.org GOTO done
:: reset to original
FOR /f "tokens=1*delims==" %%a IN (q25244121.org) DO (
 IF DEFINED %%a FOR /f "tokens=1*delims==" %%p IN ('set %%a') DO (
  IF "%%a"=="%%p" IF "%%b" neq "%%q" SET "%%a=%%b"
 )
)
:: Delete if not originally defined
FOR /f "tokens=1*delims==" %%p IN ('set') DO (
 FINDSTR /L /i /c:"%%p=" q25244121.org >NUL
 IF ERRORLEVEL 1 SET "%%p="
)

:done
:: Record current settings
set>q25244121.org

EXIT /b

This may work for you. You would need to change the SET instructions hown in CAPS to SETX. The tempfile would no doubt also need to be placed in a file where the username is part of the name you'd use.

If you were to include this batch in your startup directory, then it should restore the last-saved environment variables' values.

So, on first logon, the current variables' values are stored. On subsequent logons, the environment would be restored to those last stored, regardless of whether a setx had been executed.

You would however need to change procedures. This will restore to a known state. If you actually wanted to setx a value or install some software which adds new environment-variable values or changes existing ones (PATH would be favourite here) then you'd need to run this routine first, make the changes, delete the save file and re-run this routine. Awkward, I'll admit - but it's a way to do it.

Oh - and remember to set your variable after having setx it. You could even write a setxX batch to setx then set (or vice-versa) the required variable.