Sub-processes + error fixes. (#550)
Sub-processes + error fixes. (#550)

* nohup doesn't work with bash functions - trap HUP instead
* The env in a `trap` handler isn't this one, so can't access global
  variables. Pass it in, in sort of a try..catch pattern.
GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples,GoogleCloudPlatform/java-docs-samples