I have a windows batch command that looks something like this

cmd.exe /C testrunner.bat C:\SampleProject.xml -f C:\${env.BUILD_NUMBER}

the -f arguement for testrunner creates a folder to dump the output. I want this
folder name to be the same as the BUILD_NUMBER. However this literally creates a
folder with the name ${env.BUILD_NUMBER}

I have tried a bunch of combinations but cannot figure this out. Not sure if
this is a bug or I am doing something wrong.

Thanks

Ali