This is a shell script that uses ESXCLI 5.1 to configure SNMPv3 for an ESXi 5.1 hosts. It acccepts a single input which is a list of ESXi 5.1 hosts and before using the script, you will need to set a few variables which will be your SNMP configurations that will be applied across all hosts specifed in the input list.
For more details, please take a look at the following blog article: http://blogs.vmware.com/vsphere/?p=5593
Here is are some screenshots on how the script works:
In the screenshot, you can see the SNMPv3 configurations being applied to two ESXi 5.1 hosts. The script is just an example of showing SNMPv3 configurations, you can easily modify it to support a v1/v2c or remove uneeded v3 configurations.