If different letters appear on-screen from that which you typed, you need to reconfigure you keyboard settings. In Debian, from a command line type:
sudo dpkg-reconfigure keyboard-configuration
Or do it the cli way,From the command line type
sudo nano /etc/default/keyboard
Then find where it says
and change the gb to the two-letter code for your country…
Basically almost all indian keyboards are us based so you can change it to US..
You may need to restart for the changes to take effect.