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.
Also as it is said in drush example.aliases.drushrc.php
* Drush will search for aliases in any of these files using
* the alias search path. The following locations are examined
* for alias files:
*
* 1. In any path set in $options['alias-path'] in drushrc.php,
* or (equivalently) any path passed in via --alias-path=...
* on the command line.
* 2. In one of the default locations:
* a. /etc/drush
* b. $HOME/.drush
* c. The sites/all/drush folder for the current Drupal site
* 3. Inside the sites folder of any bootstrapped Drupal site,
* or any local Drupal site indicated by an alias used as
* a parameter to a command
So for me the first choice was to put it in sites/all/drush folder and this also worked on windows 7 localhost. When checking with command "drush sa" they were recognized.
(later I realized I have to use drush 5 (as I was on pantheon) and drush 5 has some bug with https://github.com/drush-ops/drush/issues/313 running drush from the local directory of alias, so you have to go outside but then aliases is not found anymore, so then I just put that alias file in C:\ProgramData\Drush)
Also here is nice overview what more you can do with drush
http://deeson-online.co.uk/labs/drupal-drush-aliases-and-how-use-them
Also on windows if you run into problems with drush and remote connections with SSH, you need to do this
To fix this problem with could not create directory on win 7. I managed to solve it with adding a enviroment variable to windows
right click "My Computer" choose the "Advanced system properties" link then in Advanced TAB click the "Environmental Variables" button under the "User variables" section, click "New" in "Variable name" enter in "HOME". in "Variable value" enter in the path to your profile. Like C:\Users\Marko
This solved that part of the problem.