Working with daemons
As noted in the introductory sections, daemons are a special breed of background process. Consequently, the vast majority of methods and techniques for working with processes also apply to daemons. However, there are specific commands that strictly operate on daemons when it comes to managing (or controlling) the lifetime of the related processes.
As noted in the Introducing daemons section, daemon processes are controlled by shell scripts, usually stored in the /etc/init.d/ or /lib/systemd/ system directories, depending on the Linux platform. On legacy Linux systems (for example, RHEL 6) and Ubuntu (even in the latest distros), the daemon script files are stored in /etc/init.d/. On RHEL 7/Ubuntu 18.04 and newer platforms, they are typically stored in /lib/systemd/. Feel free to do a listing of those two directories to see the contents.
The location of the daemon files and the daemon command-line utilities largely depends on the init initialization system...
