Debian systemctl config location

On a Debian system, when you start a service using sudo systemctl start xxx, the configuration file for the service xxx is typically found in one of the following locations, depending on how the service is set up:

1. /etc/systemd/system/ or /lib/systemd/system/:  
      These directories contain the systemd service unit files that describe how the service should be started, stopped, and managed. The files in /etc/systemd/system/ are system-specific overrides, while those in /lib/systemd/system/ contain default service configurations installed by packages. The service unit files have the extension .service, e.g., /lib/systemd/system/xxx.service.
2. /etc/:  
      Many services store their primary configuration files in the /etc/ directory. For example, the configuration for the Apache web server is stored in /etc/apache2/, and for Open***, it could be under /etc/open***/. The specific location varies depending on the service.

To locate the configuration file for a specific service:

• Check the systemd service unit file using:
    bash   systemctl cat xxx     This will show you the content of the service unit file, which often points to the location of the main configuration file.
• Alternatively, consult the documentation or man pages for the specific service:
    bash   man xxx