How to dockerize a project?

Dockerfile

FROM ubuntu:latest

WORKDIR /app

COPY main.sh .

input.txt

10
20
30
40
50

main.sh

#!/bin/bash

sum=0

while read num; do
  sum=$((sum + num))
done < "${1}"

echo "sum is: ${sum}" > output.txt

Problem.txt

1. A simple shell application that will take list of numbers as input and shows sum as output.

2. Input will be a text file and filename will be a cmd line argument.

3. Output will be redirected to a text file.

4. Firstly, run the program from local computer.

5. Dockerize the application for making platform independent.

* Directory structure for the project:

app
├── Dockerfile
├── input.txt
└── main.sh

Run_from_docker.txt

# Build docker for image creation
app$ sudo docker build --tag shellapp:latest .

# Run the docker container
app$ sudo docker run --name jelly_fish -v $PWD/input.txt:/app/input.txt -t shellapp:latest bash main.sh input.txt

# Show the output.txt generated within docker container
app$ sudo docker export jelly_fish > docker_container.tar
app$ mkdir docker_container
app$ tar -xf docker_container.tar -C ./docker_container/
app$ cat ./docker_container/app/output.txt
# sum is: 150

Run_from_local_computer.txt

# Run cmd
app$ bash main.sh input.txt

# Show generated output
app$ cat output.txt

Was very useful, thanks!