Linux comand: visudo

visudo

To give a user sudo permits

sudo visudo

add line:
pi ALL=(ALL) NOPASSWD: ALL
or
root ALL=(ALL:ALL) ALL

To allow some unprivileged user to run some commands with sudo:

joe ALL=(ALL) NOPASSWD: /full/path/to/command

or with some arguments:

joe ALL=(ALL) NOPASSWD: /full/path/to/command ARG1 ARG2