dnsdomainname
Show the system's DNS domain name. Note: The tool uses gethostname to get the hostname of the system and then getaddrinfo to resolve it into a canonical name. More information: <https://www.gnu.org/software/inetutils/manual/html_node/dnsdomainname-invocation.html>.
RUN apt-get update && \
apt-get install -y hostname
RUN apt-get update && \
apt-get install -y hostname
RUN pacman -S --noconfirm inetutils
RUN apt-get update && \
apt-get install -y hostname
RUN yum install -y hostname
RUN dnf install -y hostname
RUN apt-get update && \
apt-get install -y hostname