Description of problem:

In the doc https://docs.openshift.com/container-platform/4.14/virt/updating/upgrading-virt.html#virt-preventing-workload-updates-during-eus-update_upgrading-virt , we are taking backup of the current workloadUpdateMethods in a temporary variable WORKLOAD_UPDATE_METHODS. Considering that the EUS upgrade takes a lot of time, there is high chance that we may lose this value since it is only valid for current bash session. It is better to redirect the data to a temporary file instead of copying it to a variable.