Docker example

How to get going:

1. Open a terminal in the root of the project
2. Copy paste commands as desired

Build image

Normal version:

docker build -t example .

Extended version:

docker build -f Dockerfile.extended -t example2 .

Explore image layers:

dive example
# OR
dive example2

Run image

docker run --rm example
# OR
docker run --rm example2

This will use the defined CMD to be executed.

Run shell on image

docker run --rm -it example /bin/bash
# OR
docker run --rm -it example2 /bin/bash

This overwrites/replaces the default CMD with /bin/bash and gives an interactive shell (--interactive --tty or in short -it).

Note: To exit the shell: type exit or CTRL + D.

Change environment variables

Relevant option: -e <VAR_NAME>="<some-value>"

Example:

docker run --rm -e HELLO_WORLD="bye" example

With volume mount

Relevant option: -v <local-src-dir>:<container-dir>

Examples:

docker run --rm -it -v ./:/home/ugr/test example /bin/bash
# OR
docker run --rm -it -v ./:/home/ugr/test example2 /bin/bash

Change/Remove networking

Relevant option:--net <network-name>

Example:

docker run --rm -it --net none example /bin/bash

Change user

Relevant option: -u <user>

Example:

docker run --rm -u root -it example2 /bin/bash

Change working directory

Relevant option: -w <container-dir>

Examples:

docker run --rm -w /root -it example /bin/bash
# OR
docker run --rm -w /root -it example2 /bin/bash

Interesting commands to explore the shell

# Get all environment variables
env

# Echo the environment variable HELLO_WORLD (as set in the Dockerfile)
echo $HELLO_WORLD

# List files and directory in current directory (with permissions and owner)
ls -al

# List files and directory in current directory (with permissions and owner and group as id)
ls -aln

# Print current directory
pwd

# Change directory to `<path-to-directory>` (e.g. `/home`, `/`, `test`)
cd <path-to-directory>

# Print current user
whoami

# Get current user id mapping and groups
id