docker-images

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IMAGES :-
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docker build . -f <docker-file-name> -t <tag-name>   : To build docker image from docker file which is availabe in current folder. 
docker push <image-tag-name>                         : To push docker image to docker hub.
docker history <image-name>                          : To get details of each layer of image.
docker login                                         : To login to docker account


NOTE : 
docker file consists of Instructions and Arguments. 
ex:- FROM UBUNTU ( FROM :- Instructions, UBUNTU :- Argument )

Every docker image must be based half of OS or other image which is created before based on OS. 
We cannot push docker images directly to docker hub default repository ( i.e, Library). Only certified and supported images can push into 
docker hub . 
To push docker images to our account, we should first login to our account. 

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Environment Variables :-
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docker run -e <environment-variable>=<value> <image-name> : To set environment variable with in container while creating it.