When you run a command using sudo in Linux, the Terminal prompts you to type in your password with no visual feedback as you type. We’ll show a quick tweak that will show asterisks (*) when you type in your password in the Terminal.
Just run visudo and set the row
Defaults env_reset
to
Defaults env_reset,pwfeedback
or just simple add the row
Defaults pwfeedback
after the env_reset row.
The space between “Defaults” and “pwfeedback” should be a tab.
Detailed description is at HowToGeek.com.