¿Cómo usar sudo sin que pida contraseña (no es seguro)?

Ejemplo Fichero: visudo

# sudoers file.
#
# This file MUST be edited with the 'visudo' command as root.
#
# See the man page for details on how to write a sudoers file.
#

# Host alias specification

# User alias specification

# Cmnd alias specification

# Defaults

Defaults	!lecture,tty_tickets

# User privilege specification
root	ALL=(ALL) ALL

# Added by Ubuntu installer
your_system_username	ALL=(ALL) NOPASSWD: ALL