Dockerfile

FROM ubuntu:20.04
RUN apt update
RUN apt install -y tzdata

noninteractive.Dockerfile

FROM ubuntu:20.04
RUN apt update
RUN DEBIAN_FRONTEND="noninteractive" apt-get -y install tzdata

tz_env.Dockerfile

FROM ubuntu:20.04
ENV TZ=Asia/Dubai
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
RUN apt update
RUN apt install -y tzdata

tzdata.sh

Step 1/3 : FROM ubuntu:20.04
 ---> 1e4467b07108
Step 2/3 : RUN apt update
 ---> Using cache
 ---> 174ce3e1bb84
Step 3/3 : RUN apt install -y tzdata
...
Configuring tzdata
------------------

Please select the geographic area in which you live. Subsequent configuration
questions will narrow this down by presenting a list of cities, representing
the time zones in which they are located.

  1. Africa      4. Australia  7. Atlantic  10. Pacific  13. Etc
  2. America     5. Arctic     8. Europe    11. SystemV
  3. Antarctica  6. Asia       9. Indian    12. US
Geographic area: 

tzdata_docker.sh

Step 1/5 : FROM ubuntu:20.04
 ---> 1e4467b07108
Step 2/5 : ENV TZ=Asia/Dubai
 ---> Using cache
 ---> 7f4c85bd0d3e
Step 3/5 : RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
 ---> Using cache
 ---> f6f784dfbad5
Step 4/5 : RUN apt update
 ---> Using cache
 ---> 5b1b5617eaa5
Step 5/5 : RUN apt install -y tzdata
 ---> Running in e71a917a9b6b
Current default time zone: 'Asia/Dubai'
Local time is now:      Tue Aug  4 12:14:55 +04 2020.
Universal Time is now:  Tue Aug  4 08:14:55 UTC 2020.
Run 'dpkg-reconfigure tzdata' if you wish to change it.

Removing intermediate container e71a917a9b6b
 ---> 3d29f4e8f7eb
Successfully built 3d29f4e8f7eb
Successfully tagged tzdata:latest