wrote steps to install docker in readme and wrote a dockerfile for nginx not tested

README.md

@@ -9,6 +9,13 @@ This README would normally document whatever steps are necessary to get your app
 - ? what means mounted in "a file or directory on the host machine is mounted into a container" ?
 - ? why the volumes cannot be modify outside docker ?
 
+---
+## nginx basics
+
+- `sudo netstat -tulpn` to print network connections and see if nginx is running
+- or : `ps -ax | grep nginx`
+- `sudo nginx -s quit` to stop it
+
 ---
 ## Dockerfile basics
 
@@ -16,62 +23,9 @@ This README would normally document whatever steps are necessary to get your app
 - we need to copy the files it uses inside this filesystem
 - we can do that with COPY
 
-**working**
-```
-FROM scratch
-WORKDIR /
-COPY hello /
-CMD [ "/hello" ]
-```
-
-**working, when WORKDIR is absent, it's default is set to "/"**
-```
-FROM scratch
-COPY hello /
-CMD [ "/hello" ]
-```
-
-**not working, when CMD execute in shell form, instead of exec form []**
-```
-FROM scratch
-COPY hello /
-CMD /hello
-```
-
-**not working, because c executable need library <unistd.h>**
-```
-FROM scratch
-COPY hello_c /
-CMD [ "/hello_c" ]
-```
-
-**not working, when executable is copied to ".", because WORKDIR value is not "." but "/" since we gave it a relativ path so it was build in top of the implicit absolut path "/"**
-```
-FROM scratch
-WORKDIR .
-COPY hello .
-CMD [ "hello" ]
-```
-
-**not working, when WORKDIR is set to the present directory and executable is not copied, because the workdir is not the present directory but a directory in the file system of docker : executable need to be copied there to function**
-```
-FROM scratch
-WORKDIR /home/simplonco/Desktop/42/14_inception/inception/srcs/requirements/mariadb
-CMD [ "hello" ]
-```
-
-**working, because "hello" is copied to "/" and execute from "/"**
-```
-FROM scratch
-WORKDIR .
-COPY hello /
-CMD [ "/hello" ]
-```
-
 ---
 ## ressources
 
-- [how to install docker engine](https://docs.docker.com/engine/install/ubuntu/)
 - [download alpine linux](https://alpinelinux.org/downloads/)
 - [dockerhub alpine image](https://hub.docker.com/_/alpine)
 - [docker glossaire](https://docs.docker.com/glossary/)
@@ -79,13 +33,42 @@ CMD [ "/hello" ]
 - [determine the parent image](https://forums.docker.com/t/determine-the-parent-image/48611)
 - [docker image from scratch](https://codeburst.io/docker-from-scratch-2a84552470c8)
 - [build context and image context](https://stackoverflow.com/questions/55108649/what-is-app-working-directory-for-a-dockerfile/55109065#55109065)
+- [pid1 docker problem](https://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/)
 
-#### docker compose
+#### install and use docker and compose
 
+- [how to install docker engine](https://docs.docker.com/engine/install/ubuntu/)
 - [github releases](https://github.com/docker/compose/releases)
 - [install last version of compose manually](https://docs.docker.com/compose/install/compose-plugin/#install-the-plugin-manually)
 - [install manually SO discussion](https://stackoverflow.com/questions/57456212/error-version-in-docker-compose-yml-is-unsupported)
-- the version installed with is 1.17.1, way out of date
+- the version installed with apt is 1.17.1, way out of date
+
+**remove old versions**
+- `sudo apt remove docker docker-engine docker.io containerd runc`
+**preparing directory**
+- `sudo apt update`
+- `sudo apt install ca-certificates curl gnupg lsb-release`
+- `sudo mkdir -p /etc/apt/keyrings`
+- `curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg`
+- `echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null`
+**installing docker engine**
+- `sudo apt update`
+- `sudo apt install docker-ce docker-ce-cli containerd.io docker-compose-plugin`
+**check if installation worked**
+- `sudo docker run hello-world`
+**installing docker compose** checked version on github release, see above
+- `sudo curl -L "https://github.com/docker/compose/releases/download/2.10.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose`
+- `sudo chmod +x /usr/local/bin/docker-compose`
+- `sudo ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose`
+**build and run a docker image**
+- be in directory with a Dockerfile
+- `sudo docker build --tag <name> .`
+- `sudo docker images` to list images
+- `sudo docker run <name>`
+- `sudo docker image rm -f <number-id>`
+**execute a docker-compose file**
+- be in directory with a docker-compose.yml file
+- `sudo docker-compose up`
 
 #### volumes vs bind mounts