Set Ubuntu to the Korean locale.

set-locale.sh

#! /bin/bash

export DEBIAN_FRONTEND=noninteractive
export DEBCONF_NONINTERACTIVE_SEEN=true
export LANG=ko_KR.UTF-8
export LC_MESSAGES=POSIX

sed -i 's/archive.ubuntu.com/mirror.kakao.com/g' /etc/apt/sources.list
apt update -y
apt install -y locales language-pack-ko tzdata
echo "Asia/Seoul" > /etc/timezone
ln -fs /usr/share/zoneinfo/`cat /etc/timezone` /etc/localtime
locale-gen ko_KR.UTF-8
update-locale LANG=ko_KR.UTF-8
dpkg-reconfigure --frontend noninteractive locales