How to enumerate the hosts database

Enumerate the hosts database.

Display hosts database.

$ cat /etc/hosts

127.0.0.1 localhost
127.0.1.1 milosz-IdeaCentre-5-14IOB6

172.16.0.200 dell
172.16.254.254 desktop desk

192.168.56.4 example.org

Enumerate hosts database.

$ getent hosts

127.0.0.1       localhost
127.0.1.1       milosz-IdeaCentre-5-14IOB6
172.16.0.200    dell
172.16.254.254  desktop desk
192.168.56.4    example.org

Display specific host.

$ getent hosts desk

172.16.254.254  desktop desk

Check exit code to determine if host is already defined.

$ getent hosts desk >/dev/null; echo $?

0

$ getent hosts nonexistentdesktop >/dev/null; echo $?

2