Create OS user specific Drush commands I know how to create drush commands in a project, but there are a number of commands which I would like to add to my local system simply because they affect my particular workflow a lot.

In Clisp, I can define this in .clisprc.lisp. In git I can add commands to the ~/.gitconfig command, I'm looking for similar for Drush.

So, for example, I might like to have a locally defined Drush command, add-squeeky-table:

drush add-squeeky-table


And I would be able to call that on all Drupal 7 projects installed on my system.
Put your extensions in ~/.drush.

If add-squeeky-table is a drush command, put it in ~/.drush/squeekytable.drush.inc.  See drushify.

If you want to define add-squeeky-table as a shell alias, put it in ~/.drush/drushrc.php.  See the example Drush configuration file.