1. 0x01 debian

1.1. Dockerfile

# Install program to configure locales
RUN apt-get update \
    && apt-get install -y locales \
    && dpkg-reconfigure locales && \
        locale-gen C.UTF-8 \
    && /usr/sbin/update-locale LANG=C.UTF-8

# Install needed default locale for Makefly
RUN echo 'en_US.UTF-8 UTF-8' >> /etc/locale.gen \
    && locale-gen

# Set default locale for the environment
ENV LC_ALL C.UTF-8
ENV LANG en_US.UTF-8
ENV LANGUAGE en_US.UTF-8

2. 0x02 ubuntu

2.1. Dockerfile

# Set default locale for the environment
RUN locale-gen en_US.UTF-8
ENV LANG en_US.UTF-8
ENV LANGUAGE en_US:en
ENV LC_ALL en_US.UTF-8