While working on a local copy of a Drupal site I am helping develop, I ended up hitting the following error:

General error: 2006 MySQL server has gone away: SELECT ff.* FROM {filter_format} ff ...

Ugh! Now what?! We need to change a setting on MySQL that ships with MAMP. As it turns out, the default max_allowed_packet is set to 1M and it needs to be higher. Changing that to 100M did the trick for me. Locate your my.cnf file and add the following setting under the [mysqld] section:

Warning!
This article is over 2 years old and drush no longer works as it did before, so the technique described here may be harmful to your setup. However, the ability to update Drupal core is now part of drush, so just grab a recent version of it to update Drupal core for your setup.

This is just a quick note on how one can use drush to update a Drupal core from the command-line.