sudo visudo no password

To allow a user or group to sudo some commands without authentication:

Edit the /etc/sudoers file:

sudo visudo

Add a line with the username (or %group):

username ALL=NOPASSWD: HALT, REBOOT, /usr/bin/apt-get, /usr/bin/aptitude

Note: HALT and REBOOT are aliases you can add in the sudoers file, like this:

# Cmnd alias specification
Cmnd_Alias REBOOT = /sbin/reboot
Cmnd_Alias HALT = /sbin/halt

Just do 'which halt' to find the path to the executable