[docker/en] Tag long forms, Commands and minor phrasing corrections (#5421)

* phrasing correction | docker run | tag long form | secure env vars | docker build

* corrections for contribution

* rm .vscode dir

Author: 004Ajay

docker.md

@@ -15,8 +15,8 @@ needs on any machine. You can get Docker for your machine from
 [docs.docker.com/get-docker/](https://docs.docker.com/get-docker/)
 
 It has grown in popularity over the last decade due to being lightweight and
-fast as compared to virtual-machines that are bulky and slow. Unlike VMs, docker
-does not need a full blown OS of its own to be loaded to start and does not
+fast as compared to virtual-machines that are bulky and slow. Unlike VMs, Docker
+does not need a full-blown OS of its own to be loaded to start and does not
 compete for resources other than what the application it is running will use.
 VMs on the other hand are pretty resource intensive on our processors, disks and
 memory hence running multiple VMs for various applications becomes a challenge
@@ -123,7 +123,7 @@ $ docker run -d ubuntu sleep 60s
 # CONTAINER ID   IMAGE     COMMAND       CREATED         STATUS         PORTS     NAMES
 # 133261b4894a   ubuntu    "sleep 60s"   3 seconds ago   Up 2 seconds             vigorous_gould
 
-$ docker run <container-id> -p 3000:8000
+$ docker run -p 3000:8000 <image-id>
 # The -p (or --publish) flag is used to expose port 8000 inside the container to
 # port 3000 outside the container. This is because the app inside the container
 # runs in isolation, hence the port 8000 where the app runs is private to the
@@ -133,9 +133,9 @@ $ docker run -i
 # or
 $ docker run -it
 # Docker runs our containers in a non-interactive mode i.e. they do not accept
-# inputs or work dynamically while running. The -i flag keeps input open to the
-# container, and the -t flag creates a pseudo-terminal that the shell can attach
-# to (can be combined as -it)
+# inputs or work dynamically while running. The -i (or --interactive) flag
+# keeps input open to the container, and the -t (or --tty) flag creates a
+# pseudo-terminal that the shell can attach to (can be combined as -it)
 
 $ docker ps -a
 # The `docker ps` command only shows running containers by default. To see all
@@ -222,7 +222,8 @@ FROM <base-image>
 
 ENV USERNAME='admin'\
     PWD='****'
-# optionally define environmental variables
+# optionally define environmental variables, real credentials
+# should be handled more securely (like using .env file)
 
 RUN apt-get update
 # run linux commands inside container env, does not affect host env
@@ -244,15 +245,14 @@ CMD [<args>,...]
 
 ### Build your images
 Use the `docker build` command after wrapping your application into a Docker
-image to run ( or build) it.
+image to run (or build) it.
 
 ```bash
-$ docker build <path-to-dockerfile>
-# used to build an image from the specified Dockerfile
-# instead of path we could also specify a URL
-# -t tag is optional and used to name and tag your images for e.g.
-# `$ docker build -t my-image:0.1 ./home/app`
-# rebuild images everytime you make changes in the dockerfile
+$ docker build -t <image-name>:<tag> <path-to-dockerfile>
+# used to build an image from the specified Dockerfile.
+# -t (or --tag) is used to give the image a name and tag.
+# Instead of path we could specify '.' (which means,
+# check for a Dockerfile in the current directory) or a URL.
 ```
 
 ## Push your image to DockerHub