[galaxy-user] special character $ gets converted to X in tool

Hi, In a test tool that I am working on, I need to enter text preceded by a $ sign to be interpreted as an environment variable by the underlying running script. However, it seems that the $ sign gets converted to X when it gets passed to the tool executable. Is there a way to work around this or should I be doing something else to pass environment variables via Galaxy tool UI. Thanks, Ketan