ENV DEBIAN_FRONTEND noninteractive    # export DEBIAN_FRONTEND="noninteractive"

export DEBIAN_FRONTEND="noninteractive"

debconf: unable to initialize frontend: Noninteractive    # export DEBIAN_FRONTEND="noninteractive"
debconf: (Bareword "Debconf::FrontEnd::Noninteractive" not allowed while "strict subs" in use at (eval 35) line 3, <> line 1.)
debconf: falling back to frontend: Noninteractive
Subroutine BEGIN redefined at (eval 36) line 2, <> line 1.

ENV DEBIAN_FRONTEND noninteractive    # export DEBIAN_FRONTEND="noninteractive"

DEBIAN_FRONTEND

noninteractive    # export DEBIAN_FRONTEND="noninteractive"

export DEBIAN_FRONTEND='noninteractive    # export DEBIAN_FRONTEND="noninteractive"'

ARG DEBIAN_FRONTEND=noninteractive
RUN apt-get -qq install {your-package}

RUN apt-get update &&
DEBIAN_FRONTEND=noninteractive apt-get -qq install {your-package}