Linux Domain Name Variable. Domain Name System DNS provides IP address to hostname mapping. A lot of important values are stored on Linux systems in what we call variables but there are actually several types of variables and some interesting commands that can help you work with them.
The value of this variable is appended by the BIND program to any name in an A or PTR record that does not end in a period in order to create the FQDN Fully Qualified Domain Name for that host. A Domain is any tree or sub-tree within the overall domain namespace. Your computer name with Fully Qualified Domain Name FQDN.
Hostname Sample outputs vivek-laptopnixcraftin Where vivek-laptop.
ABoth Linux UNIX comes with the following utilities to display hostname domain name. Host name information is stored in a file etchostname. It used my local DNS cache server to query information. In the networking terminology the domain name is the mapping of IP with the name.