Let’s take a look at an example to understand more about ENTRYPOINT. In our example, we’ll enter a simple echo command in our Docker File and create an image and launch a container from it.

Step 1 − Build the Docker File with the subsequent commands −

FROM ubuntu MAINTAINER demousr@gmail.com ENTRYPOINT [“echo”]

Step 2 − Build the image using the Docker build command.

Step 3 − Run a container from the image.

ENV

This command is used to set environment variables in the container.

Syntax

ENV key value

Options

Key − This is the key for the environment variable.
value − This is the value for the environment variable.

Return Value

The command will execute accordingly.

Example

In our example, we’ll enter a simple echo command in our Docker File and create an image and launch a container from it.

Step 1 − Build the Docker File with the subsequent commands −

FROM ubuntu MAINTAINER demousr@gmail.com ENV var1=Tutorial var2=point

Step 2 − Build the image using the Docker build command.

Step 3 − Run a container from the image.

Step 4 − Finally, execute the env command to see the environment variables.

WORKDIR

This command is used to set the working directory of the container.

Syntax

WORKDIR dirname

Options

dirname − The new working directory. If the directory doesn’t exist, it’ll be added.

Return Value

The command will execute accordingly.

Example

In our example, we’ll enter a simple echo command in our Docker File and create an image and launch a container from it.

Step 1 − Build the Docker File with the subsequent commands −

FROM ubuntu MAINTAINER demousr@gmail.com WORKDIR /newtemp CMD pwd

Step 2 − Build the image using the Docker build command.

Page 6 Image 12 1 — docker build command

Step 3 − Run a container from the image.

So, this brings us to the end of blog. This Tecklearn ‘Instruction commands in Docker’ blog helps you with commonly asked questions if you are looking out for a job in DevOps. If you wish to learn Docker and build a career in DevOps domain, then check out our interactive, Containerization using Docker Training, that comes with 24*7 support to guide you throughout your learning period. Please find the link for course details:

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What you will Learn in this Course?

Introduction to DevOps

What is Software Development
Software Development Life Cycle
Why DevOps?
What is DevOps?
DevOps Lifecycle
DevOps Tools
Benefits of DevOps
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DevOps Implementation

Containerization using Docker – Part 1

Introduction to Docker
Understanding Docker Lifecycle
Docker Architecture
Components of Docker Ecosystem
Common Docker Operations
Committing changes in a Container
Hands On

Containerization using Docker – Part 2

Building Custom Docker Images
Docker Image
Introduction to Docker Swarm
Deploying a 2-Node Cluster using Docker Swarm
Hands on

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