Docker minihowto

To start a new container. If does not exists locally, it downloads a stock one from dockerhub.
docker run -i -t centos:latest /bin/bash
(-i: interactive mode) (-t: runs centos image) (starts a command, here a shell)
List running docker containers: docker ps
List running docker containers + history : docker ps -a
List docker local images: docker images
Escape from a container and put that running one in the background: CTRL-P+CTRL-Q - or run it with -exec: docker exec -ti [CONTAINER-ID] bash
It starts a new process with bash shell, and you could escape from it by ^c directly, it won't affect the original process.

On the host find the docker virtual files (aufs), confs, etc. here: /var/lib/docker
See details about an image: docker inspect IMAGENAME(e.g. centos:latest)OR ITS_RANDOM_NAME | less
To build a new container: docker build -t MYIMAGENAME . (.=where my DOCKERFILE is)
an example DOCKERFILE content looks like:

FROM ubuntu:latest
RUN apt-get update
RUN apt-get install -y wget
RUN apt-get install -y build-essential tcl8.5
RUN wget http://download.redis.io/releases/redis-stable.tar.gz
RUN tar xzf redis-stable.tar.gz
RUN cd redis-stable && make && make install
RUN ./redis-stable/utils/install_server.sh
EXPOSE 6379
ENTRYPOINT  ["redis-server"]

To see the standard output of a container: docker logs CONTAINERNAME
docker run -d centos:latest -p 3000:3000 --name my-service (starts in the background) (maps hosts's port 3000 (on all interfaces) to container's service port 3000)
To enter inside a container with bash:  docker exec -i -t my-service /bin/bash
Tag (set an alias name for) an image: docker tag IMAGE_ID (seen in the output of docker images) REPONAME:TAG (e.g. mydockeruser/myrepo:2)
Now see what you have tagged: docker images
Enter dockerhub with your dockerhub login: docker login
Push your new built image into your pub repository: docker push REPONAME:TAG
Remove an image from localhost repository: docker rmi IMAGE_ID (force with -f)
For example, to start a new mariadb instance:
docker run --name mariadb-1 -p 3306:3306 -e MYSQL_ROOT_PASSWORD=mypass -v /home/ubuntu/db/db1:/var/lib/mysql -d mariadb
(with -v you mount your localhost's folder into your container)(with -e you pass an environment variable to the container.
Passing a global variable, for example: docker run -i -t -e "WHOISTHEKING=me" ubuntu:14.04 /bin/bash -> echo $WHOISTHEKING)
Insert a file into the container directly from outside:
docker insert CONTAINERNAME http://ftp.drupal.org/files/projects/drupal-7.22.tar.gz /root/drupal.tar.gz
To commit your changes to the image: docker commit -m "commit message" -a "Your Name" IMAGENAME username/my-redis:latest TO BE CONTINUED