Dockerfile

FROM ubuntu:24.04

# Avoid interactive prompts during apt operations
ENV DEBIAN_FRONTEND=noninteractive

# Base tools + locale support + zsh + optional utilities.
RUN apt-get update && \
    apt-get install -y \
      sudo dialog vim git curl locales python3-pip zsh \
      net-tools apt-utils openssh-server \
      htop tree glances && \
    rm -rf /var/lib/apt/lists/*

# Generate UTF-8 locale and set it as default.
RUN locale-gen en_US.UTF-8 && \
    update-locale LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8

ENV LANG=en_US.UTF-8
ENV LC_ALL=en_US.UTF-8

# Create a non-root user with sudo privileges.
# NOTE: We keep GID/UID fixed for convenience when bind-mounting from host.
RUN groupadd -g 1100 user && \
    useradd -r -m -d /home/user -s /usr/bin/zsh -g root -G sudo -u 1100 user

# sshd needs its runtime directory. This is harmless even if you do not use ssh.
RUN mkdir -p /var/run/sshd
CMD ["/usr/sbin/sshd", "-D"]

EXPOSE 22
WORKDIR /home/user

# EOF