Why does sudo ask for a password in terminal?

Solution 1:

sudo su asks for a password on my system. Did you run another sudo command before the sudo su? Once you've run sudo and entered your password, it doesn't require a password again for a period of time.

Solution 2:

You can just modify following lines in /etc/sudoers :

# 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

to

# Members of the admin group may gain root privileges
%admin ALL=(ALL) NOPASSWD: ALL

# Allow members of group sudo to execute any command
%sudo  ALL=(ALL:ALL) NOPASSWD: ALL