I don't know right now. My coffee effects are not showing up yet :-)

15:59:45 rrs@zan:~/devel/Laptop-Mode-Tools/laptop-mode-tools (lmt-upstream)$ echo $x 
x
16:00:40 rrs@zan:~/devel/Laptop-Mode-Tools/laptop-mode-tools (lmt-upstream)$ echo $y

16:00:42 rrs@zan:~/devel/Laptop-Mode-Tools/laptop-mode-tools (lmt-upstream)$ test -e x$x x$y
bash: test: xx: binary operator expected
16:00:54 rrs@zan:~/devel/Laptop-Mode-Tools/laptop-mode-tools (lmt-upstream)$ test x$x = x$y
16:01:38 rrs@zan:~/devel/Laptop-Mode-Tools/laptop-mode-tools (lmt-upstream)$ test $x = $y
bash: test: x: unary operator expected
16:01:45 rrs@zan:~/devel/Laptop-Mode-Tools/laptop-mode-tools (lmt-upstream)$ test $x != $y
bash: test: x: unary operator expected
16:01:58 rrs@zan:~/devel/Laptop-Mode-Tools/laptop-mode-tools (lmt-upstream)$ test x$x != x$y
16:02:02 rrs@zan:~/devel/Laptop-Mode-Tools/laptop-mode-tools (lmt-upstream)$ 


Someday, I'd just want to rewrite the entire thing in Python with a feature for feature parity.