barracuda@barracuda-Lenovo-G550:~$ hostname
barracuda-Lenovo-G550
barracuda@barracuda-Lenovo-G550:~$ sudo hostname
sudo: unable to resolve host barracuda-Lenovo-G550
[sudo] password for barracuda:
barracuda-Lenovo-G550
barracuda@barracuda-Lenovo-G550:~$ sudo hostname
sudo: unable to resolve host barracuda-Lenovo-G550
barracuda-Lenovo-G550
barracuda@barracuda-Lenovo-G550:~$ cat /etc/hosts
127.0.0.1	localhost
::1		barracuda-Lenovo-G550
127.0.1.1	barracuda-Lenovo-G550

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
barracuda@barracuda-Lenovo-G550:~$ cat /etc/hostname
barracuda-Lenovo-G550
barracuda@barracuda-Lenovo-G550:~$ cat /etc/nsswitch.conf
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.

passwd:         compat
group:          compat
shadow:         compat

hosts:          dns
networks:       files

protocols:      db files
services:       db files
ethers:         db files
rpc:            db files

netgroup:       nis
barracuda@barracuda-Lenovo-G550:~$