CentOS

For CentOS, the DIG tool is a part of the BIND Utilities so you need to install them.

# yum whatprovides '*bin/dig'

To install the BIND Utilities, type the following:

# yum install bind-utils

Debian

Update Debian

 $ sudo apt update

Install dnsutils package with the following command:

$ sudo apt install dnsutils -y

Check dig

dig -v
DiG 9.11.5-P4-5.1+deb10u5-Debian