What determines the environment for $ZF(-1)?

Hello,

I'm using $ZF(-1) in a class method which will be invoked from a csp page.

What determines the environment of the spawned process?  If I use $ZF(-1,"echo hello world > output.txt"), the resulting file is owned by cacheusr:cacheusr.  However, when I use $ZF(-1,"printenv > output.txt"), the environment is from my personal unix account, no matter which Cache username I'm logged in under when running the web application.  

Thanks