Arvados

Currently there is no bulk update API in Arvados. Therefore, in order to update a large number of entities using the CLI one has to loop through them and do an "update" on each one. Once the update is applied, the update command returns the full record for the entity, which can be wasteful and time consuming. For example, when updating the 'replication_desired' property on a collection, the update CLI call returns the full collection record including the manifest, which is very large. For my use case, I do not require the full entity record, just a confirmation that the property I have updated has been set.

It could be an easy improvement in the performance using the CLI update method to implement the same sort of column selection behaviour as is in the `list` method. As long as the default remains returning the full record, this should be a backwards compatible addition to the CLI.