1) install the required packages
apt-get install libpam-fprint fprint-demo
2) restart the machine
3) Run 'fprint_demo' and press 'Enroll' button in front of 'Right index finger' sweep your right index finger two three times to get a better scan then press ok and store the print.
4) Go to 'identify' tab of 'fprint_demo' check weather it can identify you finger and remember the starting pont, motion, and end point of you finger when it identifies you.
5) Edit /etc/pam.d/common-auth and include bellow line on top of all the active entris in the file
'auth sufficient pam_fprint.so'
6) Thats it, now logout and login to test the settings. In the login page first you have to enter your username then it will hold on untill you sweep your finger and will give you number of tries like 5. If you failed to sweep your finger in correct wey it will prompt for password.
7) To aunticate sudoers with fingerprint you can add bellow entry to the top of the 'session' entries in /etc/pam.d/sudo
'session sufficient pam_fprint.so'
8) Now try to execute a command in your terminal with sudo it will ask for the finger sweep and if you fail to sweep in correct wey it will prompt for password