File Permissions
OpenDXP requires write access to the following directories: /var and /public/var.
If you know which user executes PHP on your system (PHP-FPM user, Apache user, ...), simply give write access to the appropriate user.
Execute the following commands on the shell (eg. via SSH, …) in your install directory - replace YOURUSER and YOURGROUP with your configuration:
chown -R YOURUSER:YOURGROUP var public/var
You can get further generic information about Symfony file permissions here: Symfony file permissions.
To be able to execute cli tools (opendxp or symfony console for instance), you need to give execute permissions to the cli tools. Here it add execute permissions to the user and group:
chmod ug+x bin/*