Question: entering docker port

[Tayumakio]

While trying to install the service through the new nginx configuration, I repeatedly encountered an error after entering docker port: 8080 already in use.

Docker has been configured by your script and running the script again causes this error.
Docker itself already running and listening on this port. There wasn't a single container running in it, but your script still gave an error.
It seems to me that this is the wrong behavior for a script.

[m1k1o]

Check if something else is not listening on the port:

sudo netstat -ntlp

If the netstat command is not available, install it with:

sudo apt install net-tools

[Tayumakio]

Yep, I checked it before:
sudo lsof -nP -iTCP -sTCP:LISTEN

After reboot of system it was like that.
Then I stoped docker service and script works without error
sudo systemctl stop docker.service