Prevent mistaking inherited environment variables as arguments

[kittydoor]

In my shell profile, I set a variable called "FILE" which points to my file manager of choice. Same thing with "BROWSER", "EDITOR", etc.

However, flash doesn't take into account that a generic name like FILE might already exist in the environment, and mistakes it for an argument passed to itself.

Setting values to a default (e.g. ""), would resolve this and simiilar unexpected behaviour.