Where is drush installed (using drush sup and search for alisases.drushrc.php)

Maybe you are wondering the same thing as I, where the heck is my drush installed. Easiest way is to write "find / -name 'drush' -type d" and you will get info. So finally you know where that alisases.drushrc.php is and you can go and add configuration for drupal 6 to drupal 7 migration.

If this doesn't help you, try commands

which drush or drush status

Usually you would find drush in /usr/share/php/drush or /usr/share/drush and aliases file is in that directory as well.