wp-cli Enabling Maintainance Mode

During theme or plugin upgrades, maintenance mode is enabled and then disabled once complete.

Is it possible to manually enable / disable maintenance mode?

Enabling Maintenance mode...
Downloading update from xxxx
Disabling Maintenance mode...

WP-CLI now has native commands for it.

# Activate Maintenance mode
$ wp maintenance-mode activate
# Deactivate Maintenance mode
$ wp maintenance-mode deactivate

See wp-cli/maintenance-mode-command for more information.