Run sudo command without a password

1. Open /etc/sudoers with visudo editor, as if straight away edit /etc/sudoers file with text editor, it won't validate the syntax.

   sudo visudo

2. Append this line username ALL=(ALL:ALL) NOPASSWD:ALL at the end of the /etc/sudoers file

   /etc/sudoers

   # User privilege specification
   root    ALL=(ALL:ALL) ALL
    
   # Members of the admin group may gain root privileges
   %admin ALL=(ALL) ALL
    
   # Allow members of group sudo to execute any command
   %sudo   ALL=(ALL:ALL) ALL
    
   # See sudoers(5) for more information on "@include" directives:
    
   @includedir /etc/sudoers.d
   kc      ALL=(ALL:ALL) NOPASSWD:ALL

3. Open a new terminal window and test the command with root privileges

   sudo apt-get update