+# Minimalist version of cleanup, used for signal handling.
+# Sends a SIGKILL to the entire process group, including ourselves.
+# Needs just two external commands, making it more
+# robust in case of resource issues.
+panic() {
+ echo "$0(pid $$): Caught a signal, emergency clean-up"
+ # use "pgid:1=" output format to get unpadded process group ID
+ group_id=`ps -p $$ -o pgid:1=`
+ echo "$0(pid $$): sending kill to process group ID:${group_id}"
+ kill -9 -- -${group_id}
+ # not reached
+}
+
+# Happy camper leisurely clean up - send the signal only to other
+# processes in the process group, and also check
+# that the processes exists before sending the signal.