trap: 8
+[9] echo 4
4
+exit subshell 1
+current shell
+exit subshell 2
+current shell
+current shell
+current shell
+outside 1
+outside 2
+outside 3
+outside 4
+sleep 2
+wait $!
+exit
+in trap EXIT
+sleep 2
+wait $!
+exit
+in trap EXIT
caught a child death
caught a child death
caught a child death