# Detect EOF and print all except that last line:
while [ -z "$(tail -1 sigusr2.out | grep ^EOF)" ]; do sleep 0.1; done
-head --lines=-1 `pwd`/sigusr2.out
+head --lines=-1 sigusr2.out
+exception=$(grep exception sigusr2.out)
+[ $? -eq 0 ] && _exit "(detected 'exception' within operation output)"
+exit 0