Ah, that's interesting. See, I've relied on the value set in this variable to determine what shell I was running. Now that it's not consistent, I'm confused.
When I run the echo command from within my login shell I get the following:
No file for $0
But, invoking bash beforehand it tells me what I have correctly:
bash-2.03$ echo $0
So even though this variable is incorrect I can assume that when I run 'bash' I am in the BASH shell? A silly question, but having made this assumption in the past that's what I looked at... Oh and I am using telnet not ssh if that makes a difference (for reasons I have no authority over).