How to use setx command in a windows batch file

Question

I am trying to create a windows batch file to automatically set the environment variable to use python 2.4 or python 3.3.

Both python 2.4 and 3.3 are installed on my sys

Answer 1

SETX requires values with spaces to be quoted, and quotes within the value must be escaped as \".

Best also to use delayed expansion to protect against special characters during the batch parsing phase.

The following will not only toggle the values for new CMD sessions, it will also toggle the value for the remainder of the batch script run. An implicit ENDLOCAL at the end of the script will revert to the old values within the current session once the script ends. If needed, the script can be modified to preserve the new values past the ENDLOCAL barrier.

@echo on
setlocal enableDelayedExpansion
if "!PYTHONHOME:~-2!" == "24" (
  set "PYTHONHOME=C:\Python33"
  set "PATH=!PATH:Python24=Python33!"
) else (
  set "PYTHONHOME=C:\Python24"
  set "PATH=!PATH:Python33=Python24!"
)
setx PYTHONHOME "!home!"
setx PATH "!path:"=\"!"
pause