If you want to roll just the go/ directory of noms, you can do:
$ roll.py https://github.com/attic-labs/noms --incl go
If you want to roll the AWS SDK without the tests, you can do:
$ roll.py https://github.com/aws/aws-sdk-go --excl awstesting
This works with nested directories too, for example --incl go/util
--excl is evaluated after --incl, so you could exclude the perf/
directory of go/ if you really wanted:
$ roll.py https://github.com/attic-labs/noms --incl go --excl go/perf
Ben Kalman