How do I use cv to run database upgrades from the command line?
The cv upgrade:db command from https://github.com/civicrm/cv/pull/2 was recently merged for v0.2.3. This revision hasn't been broadly deployed or tested yet, but it provides a richer upgrade experience:


By default, there's a progress indicator.
With -vvv, you can get a detailed report/log of the upgrade steps as they execute.
With -vvv --dry-run, you can see a detailed preview of the upgrade steps.
With --retry or --skip, you can resume after an upgrade failure.
With --quiet, you can limit output to particularly interesting information.


I've found that -vvv and --dry-run are helpful when developing patches for the civicrm-core upgrade logic, and they may also be helpful with large or temperamental upgrades.

(Note: PR #2 also anticipates several more subcommands for identifying/downloading upgrades and for reporting successes and failures. However, these are not live at time of writing)