Ubuntu ERROR: sudo: unable to resolve host ubuntu: Name or service not known
ubuntu系统报错：sudo: unable to resolve host ubuntu: Name or service not known
检查一下，
ubuntu@ubuntu:~/mc$ cat /etc/hostname
ubuntu
ubuntu@ubuntu:~/mc$ cat /etc/hosts
127.0.0.1 localhost
# 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
ff02::3 ip6-allhosts
修改一下，
sudo vim /etc/hosts添加了一行"127.0.1.1 ubuntu"（也可以是127.0.0.1 ubuntu），如下，
127.0.0.1 localhost
127.0.1.1 ubuntu
# 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
ff02::3 ip6-allhosts
再检查
username@ubuntu ~ $ cat /etc/hostname
ubuntu
username@ubuntu ~ $ cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 ubuntu
# 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
ff02::3 ip6-allhosts问题解决。