Drush is fast for updateing modules, now there is also add on for upgrading modules from drupal 6 to drupal 7. You need to install http://drupal.org/project/drush_sup
Everything you need is in readme file, but the one important thing. You need to set alias for your new destination, your drupal 7 site version destination so you don't overrun drupal 6 and lose your original. But the problem is that you will get
Site alias not found: @test. See example.drushrc.php.
Unless you edit your aliases.drushrc.php and add to it, this is not said and by default you get aliases.drushrc.php file without this, at least now it is like that, hope it will be changed as it is confusing. So you need to have file like this.
<?php
$aliases['test'] = array(
'root' => '/srv/www/dump',
'uri' => 'drupaldump.com',
);
?>and then run drush site-upgrade @test
Also an important notes.
-run drush site_update @some_alias from the root of your drupal installation
-use chown-R current_user:www-data /drupal_site otheerwise you will get bunch of errors like these and you will go crazy trying to find a solution which doesn't have any connection to errors below.
Command site-upgrade needs a higher bootstrap level to run - you will need invoke drush from a more functional Drupal environment to run this command. [error]
Command site-upgrade needs the following modules installed/enabled to run: update. [error]
The drush command 'sup' could not be executed. [error]
Drush was not able to start (bootstrap) the Drupal database. [error]
Hint: This error often occurs when Drush is trying to bootstrap a site that has not been installed or does not have a configured database.
You can also try in drupal directory
drush sa @self
or
drush sa --with-db @self
To manually create alias and get an output of it and then just copy paste it to aliases.drushrc.php