true; ``; echo $?
false; ``; echo $?
-# UNFIXED BUG. bash sets $? to 127:
true; `""`; echo $?
-# bash sets $? to 127:
false; `""`; echo $?
true; ` `; echo $?
false; ` `; echo $?
true; $(); echo $?
false; $(); echo $?
-# bash sets $? to 127:
true; $(""); echo $?
-# bash sets $? to 127:
false; $(""); echo $?
true; $( ); echo $?
false; $( ); echo $?