docs: useradd issue

[adrianrudnik]

What happened?

I'm currently working through https://frankenphp.dev/docs/docker/#running-with-no-capabilities and see the line useradd -D ${USER}; mentioned several times.

Following through the example:

docker run -it --rm dunglas/frankenphp bash
export USER=www-data
useradd -D ${USER}

just prints the commands help.

-D for useradd is print or change default useradd configuration.
-D for adduser is Don't assign a password

From my understanding the intention is to add a user www-data without a password on debian? That would be useradd without specifying -p. But even then

cat /etc/passwd | grep www-data

show the user already exists, so can it be omitted because it serves nothing?

Build Type

Docker (Debian Bookworm)

Worker Mode

Yes

Operating System

GNU/Linux

CPU Architecture

x86_64

PHP configuration

The one installed in the docker image dunglas/frankenphp

Relevant log output

No response

[adrianrudnik]

In addition, in the upstream image, the home folder for the user www-data is configured to be /var/www:

cat /etc/passwd | grep www-data
> www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin

but the user has no access to it, as everything is owned by root

ls -ldh /var/www
drwxr-xr-x 3 root root 4.0K Nov 21 17:54 /var/www

Any reason why /app is preferred over `/var/www'?