docker build

Turn a Dockerfile into an image you can run, with a name and a version tag.

>_ Try it: a simulated Linux, right herenothing runs on your computer

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Examples

docker build -t my-app:v1 . build version 1
docker images your image is in the list
docker run -d -p 4000:3000 --name my-app my-app:v1 run it like any other image
curl localhost:4000 see it answer
docker build -t my-app:v2 -f Dockerfile . a second version, naming the Dockerfile

How it works

docker build reads the Dockerfile (the recipe: base image, files to copy, commands to run) and makes an image from it, layer by layer.

-t name:tag gives the image a name and a version, so you can run it with docker run name:tag. The . at the end is the build context: the folder whose files the Dockerfile can copy.

Syntax

docker build [OPTIONS] PATH

Options

Option	What it does
`-t`	name and tag the image: NAME:TAG
`-f`	use another Dockerfile
`.`	the build context: this folder

Good to know

Each Dockerfile line is a layer. Docker reuses the layers that didn't change, so put the lines that change most (like COPY . .) near the end.
Without -t the image has no name, only an ID: you will want the name later.