How to copy files from host to Docker container?

Question

I am trying to build a backup and restore solution for the Docker containers that we work with.

I have Docker base image that I have created, ubuntu:base

Answer 1

Typically there are three types:

1. From a container to the host

   docker cp container_id:./bar/foo.txt .
   

2. From the host to a container

   docker exec -i container_id sh -c 'cat > ./bar/foo.txt' < ./foo.txt
   

3. From a container to a container mixes 1 and 2

   docker cp container_id1:./bar/foo.txt .
   
   docker exec -i container_id2 sh -c 'cat > ./bar/foo.txt' < ./foo.txt