case w in a) echo SKIP;; w) echo OK_1;; w) echo WRONG;; esac

case w in
 a) echo SKIP;;
 w)echo OK_1 ;;
 w)
 echo WRONG
 ;;
esac

t=w
case $t in a) echo SKIP;; w) echo OK_21;; w) echo WRONG;; esac;
case "$t" in a) echo SKIP;; w) echo OK_22;; w) echo WRONG;; esac;
case w in a) echo SKIP;; $t) echo OK_23;; "$t") echo WRONG;; esac;

case '' in a) echo SKIP;; w) echo WRONG;; *) echo OK_31;; esac;
case '' in a) echo SKIP;; '') echo OK_32;; *) echo WRONG;; esac;

case `echo w` in a) echo SKIP;; w) echo OK_41;; w) echo WRONG;; esac;
case "`echo w`" in a) echo SKIP;; w) echo OK_42;; w) echo WRONG;; esac;
case `echo w w` in a) echo SKIP;; w) echo WRONG;; 'w w') echo OK_43;; esac;
case `echo w w` in a) echo SKIP;; w) echo WRONG;; w*) echo OK_44;; esac;

case w in `echo w`) echo OK_51;; `echo WRONG >&2`w) echo WRONG;; esac;
case w in `echo OK_52 >&2`) echo SKIP;; `echo`w) echo OK_53;; esac;

# parsing cases in subshells can easily get messy
 case m in  m) echo OK_sub1;; esac
 case m in (m) echo OK_sub2;; esac
(case m in  m) echo OK_sub3;; esac)
(case m in (m) echo OK_sub4;; esac)
(
 case m in  m) echo OK_sub5;; esac
)
(
 case m in (m) echo OK_sub6;; esac
)
(case esac in "esac") echo OK_esac1;; esac)

echo Done