You can use netconfig (part of RME) to do this task. Very simple to do, just be careful since netconfig does not validate your configuration for context (it doesn't even verify the config command is valid) NOR does it do any integrity checking to see if you are not making a major bone-head move. Use with caution, however, changing the community strings is something you can recover from if you do it incorrectly. Suggestion, test with a few switches as a pilot