Example file for assignment Z3.1 (course VPS and Linux server administration).
Server web1.example.com. The web server (nginx with PHP-FPM) runs as user www-data.

anna@web1:~$ id anna
uid=1000(anna) gid=1000(anna) groups=1000(anna),27(sudo)

anna@web1:~$ id jan
uid=1001(jan) gid=1001(jan) groups=1001(jan),33(www-data)

anna@web1:~$ id backup
uid=1002(backup) gid=1002(backup) groups=1002(backup)

anna@web1:~$ id www-data
uid=33(www-data) gid=33(www-data) groups=33(www-data)

anna@web1:~$ ls -la /var/www/example.com
total 40
drwxr-x--- 5 anna     www-data  4096 Nov  9 10:00 .
drwxr-xr-x 3 root     root      4096 Nov  1 09:00 ..
-rw-rw-rw- 1 anna     www-data   612 Nov  9 10:01 .env
-rw-r----- 1 anna     www-data   412 Nov  9 10:02 config.php
-rw-r--r-- 1 anna     www-data  1520 Nov  9 10:03 index.php
drwxr-xr-x 2 anna     www-data  4096 Nov  9 10:07 images
drwx------ 2 anna     anna      4096 Nov  9 10:05 prive
drwxrwxr-x 2 www-data www-data  4096 Nov  9 10:04 uploads
-rwsr-xr-x 1 root     root     16400 Nov  9 10:06 opruimen

Questions (answer with yes/no, a file name or a number):
1. Can the web server (www-data) read config.php?
2. Can the web server (www-data) modify config.php?
3. Which file can be modified by any user on the server?
4. Which permissions (as a number) suit that file, if the web application needs to be able to read it?
5. Can jan delete someone else's files in the uploads directory?
6. Can jan open the prive directory?
7. Which file runs with the permissions of root, even when a regular user starts it?
8. Can the user backup read the file index.php?
9. What are the permissions of the uploads directory as a number?