where can i find houdini.env?

it should be in your $HOME/houdini directory (on linux) and probably in Document and Settings\username\houdini on windows.

I am using Mac Snow Leopard.

On OS X it is located here: ~/Library/Preferences/houdini/X.Y/houdini.env

is it possible to have the value run some script or unix command before making the variable assignment? ie ‘unix echo “hello world”’… looks like environment variables can be resolved in the value. but is that the extent of the syntax?