Docker ps -a: This command is used to know the details of all the running, stopped, or exited containers.

Docker version: We usually start by finding the installed version of docker that we are working on.

Docker pull: As the name suggests, this command pulls a specific image from the Docker Hub. All you have to do is use the command ‘docker pull’ along with the name of the image. Here is an example of pulling an image without using the tag.

Docker run: This command is used to create a container from an image.

Docker stop: The ‘docker stop’ command stops a container using the container name or its id.

Docker restart: This command is used to restart the stopped container. It is recommended to use this after rebooting the system.

Docker kill:This command is used to stop the container immediately by killing its execution. While the ‘docker stop’ command helps shut down the container in its own time, the ‘docker kill’ command stops it at once.

Docker login:This command helps you to log into your docker hub. As you try to log in, you will be asked to give your docker hub credentials.

Docker network:The ‘docker network’ command is used to know the details of the list of networks in the cluster.

Docker-compose down: You need to stop all services declared in a docker-compose file.
Docker-compose logs: Your service crashed on launch and you want to know why.
Docker-compose stop: You want to stop your container by service name or container name.
Docker-compose restart: You want to restart a container with the service name or container name.

Docker-compose exec:  You want to access inside the launched container and execute something, similar with docker exec. 
Docker-compose down: You need to stop all services declared in a docker-compose file.
Docker rmi:  You need more space on your disk.      

• CMD: Sets default command and parameters, which can be overwritten from command line when Docker container runs.

• ENTRYPOINT: Command and parameters will not be overwritten from command line. Instead, all command line arguments will be added after entry points parameters.

• ADD:  Add the files to the images.
• COPY:  Used to copy files and directories inside a Docker container from your Local machine.
• EXPOSE: The instruction exposes a particular port with a specified protocol inside a Docker Container. 
• FROM: To pull base images like alpine,ubuntu,etc.
• LABEL: Labels are used in Dockerfile to help organize your Docker Images.
• USER: We are going to use the user instruction to switch the user inside the Container from Root to the one which we will create. 

• WORKDIR:  Instruction is used to set the working directory for all the subsequent Dockerfile instructions. 

Docker client and server: Docker Engine is installed on the server side and the client side just consist of the Command Line Interface used for issuing commands to Docker Engine.

Docker image: A Docker image is a file used to execute code in a Docker container.
 
Docker registry:  A Docker registry is a storage and distribution system for named Docker images.

Docker container: A Docker container image is a lightweight, standalone, executable package of software that includes everything needed to run an application.
 

Docker search 
The “docker search” command searches for specific images through the Docker hub. This command returns the specific information, including image name, description, automated, official stars, etc.

Docker pull
As the name suggests, this command pulls a specific image from the Docker Hub. All you have to do is use the command ‘docker pull’ along with the name of the image. Here is an example of pulling an image without using the tag. 

Docker run 
This command is used to create a container from an image.

Docker ps
This command is used to list all the running containers in the background. 

Docker stop 
The ‘docker stop’ command stops a container using the container name or its id. 

Docker restart 
This command is used to restart the stopped container. It is recommended to use this after rebooting the system.

Docker kill
This command is used to stop the container immediately by killing its execution. While the ‘docker stop’ command helps shut down the container in its own time, the ‘docker kill’ command stops it at once.

Docker exec 
This command is used to access the container that is running. 

Docker login
This command helps you to log into your docker hub. As you try to log in, you will be asked to give your docker hub credentials. 

Docker commit 
This command is used to create or save an image of the edited container on the local system. 

Docker push 
This command helps push or upload a docker image on the repository or the docker hub. 

Docker network 
The ‘docker network’ command is used to know the details of the list of networks in the cluster. 

Docker rmi 
This command is used to free up some disk space. The image id is used to remove the image while using this command.

Docker ps -a
This command is used to know the details of all the running, stopped, or exited containers. 

Docker copy
This command copies a file from docker to the local system.

Docker logs  
This command is used to check the logs of all the docker containers with the corresponding contained id mentioned in the command.

Docker volume 
This command creates a volume so that the docker container can use it to store data.

Docker logout 
This command will log you out of the docker hub. 

difference between pause and unpause
docker pause will suspends all the processes inside the container,where as unpause will resume the processes

Difference between kill and stop
Docker kill will kill one or more containers .Docker stop will stop the running container

What is the difference between docker pause and unpause?pause: to stop the process running inside containers.
unpause- to resume the paused process inside containers.

What is the difference between docker stop and kill?Docker stop: stop a running container
Docker kill: kills a running container.

What is the difference between docker exec and attach?Docker exec: will enter into the container and start interacting.
by using >> docker exec -it NAME /bin/bash
Docker attach: it will directly take us to PID 1 of the container, we use this for troubleshooting
by using docker attach NAME
List of docker file instructions and its Brief Summary?FROM: create a base image like httpd , ubuntu.
RUN: to build the container
MAINTAINER: creator of images.
ENV: an environment for image
COPY: copy the file to images
What is the difference between CMD vs EntrypointENTRYPOINT: act as an entry point to the container.
CMD: we use to set the commend it will execute while running the container.

2. What is the difference between docker pause and docker unpause? Docker pause suspends all the process to container. 
Docker unpause will un-suspend all the process to container.

3. docker stop: Stop a running container (send SIGTERM, and then SIGKILL after grace period) The main process inside…
  docker kill: Kill a running container (send SIGKILL, or specified signal) The main process inside the container…

4. Both docker exec and attach are used to connect or access the container but only difference is that docker exec creates a 
differrent process to access the container whereas docker attach connects to the same standard input/out or the same terminal.

5. There are a variety of Dockerfile instructions we can put in our Dockerfile. These include FROM, RUN, WORKDIR, COPY, ADD, VOLUME, CMD, ENTRYPOINT, WORKDIR, USER, ONBUILD, LABEL, ARG, SHELL, HEALTHCHECK, EXPOSE and ENV. 
You can see a full list of the available Dockerfile instructions here.

6. ENTRYPOINT should be defined when using the container as an executable. CMD should be used as a way of defining default arguments for an ENTRYPOINT command or for executing an ad-hoc command in a container. 
CMD will be overridden when running the container with alternative arguments.