Mass password reset

Maybe you'd like to reset password for all users, but don't want to do this one by one.
Here is the way to do it :
- reset password for 1 user and save changes
- export users list in CSV format
- open the exported CSV file
- find the user you updated, and copy his password (it's a crypted value)
- paste this password for all the other users
- clear all fields excepts "id" and "password"
- save your CSV file
- import this CSV file as users using the import functionality
That's all.