I want to build my own custom docker image from nginx image.

I override the ENTRYPOINT of nginx with my own ENTERYPOINT file.

Which bring me to ask two questions:

1. I think I lose some commands from nginx by doing so. am I right? (like expose the port.. )
2. If I want to restart the nginx I run this commands: `nginx -t && systemctl reload nginx`. but the output is:

`nginx: configuration file /etc/nginx/nginx.conf test is successful`

`/entrypoint.sh: line 5: systemctl: command not found`

How to fix that?

```
FROM nginx:latest

WORKDIR /

RUN echo "deb http://ftp.debian.org/debian stretch-backports main" >> /etc/apt/sources.list

RUN apt-get -y update && \
    apt-get -y install apt-utils && \
    apt-get -y upgrade && \
    apt-get -y clean

# I ALSO WANT TO INSTALL CERBOT FOR LATER USE (in my entrypoint file)

RUN apt-get -y install python-certbot-nginx -t stretch-backports

# COPY ./something ./tothisimage 
# COPY ./something ./tothisimage 
# COPY ./something ./tothisimage 
# COPY ./something ./tothisimage 

COPY entrypoint.sh /entrypoint.sh

ENTRYPOINT ["bash", "/entrypoint.sh"]

```

**entrypoint.sh**

```
echo "in entrypoint"

# I want to run some commands here... 

# After I want to run nginx normally....

nginx -t && systemctl reload nginx

echo "after reload"

```