I am using 'zsh' by default.
But when I am in my zsh shell, I enter 'bash' to switch to bash, why the $SHELL variable does not change?
Can I make screen to use whatever shell I right before execute the 'screen' command?
zsh % screen
<the shell is zsh>
zsh % bash
bash $ screen
<the shell is still bash, can I make screen to automatically start bash here>