AsError extracts the Error from err's error tree or (nil, false) if none exists.

ClassifyCmdError classifies an error received while executing a non-cockroach command remotely over an ssh connection to the right Error type.

SelectPriorityError selects an error from the list in this priority order: - the Error with the highest exit code - one of the `error`s - nil.

Cmd wraps errors that result from a command run against the cluster.

SSH wraps ssh-specific errors from connections to remote hosts.

Unclassified wraps roachprod and unclassified errors.

Error is an interface for error types used by the main.wrap() function to output correctly classified log messages and exit codes.