Linux Processes, Services, and Apps are core components that manage system tasks, background operations, and user interaction.
Processes are running instances of programs, identified by a Process ID (PID), managed by the kernel. They can run in the foreground or background and include special types like daemons (long-running) and zombies (terminated but not cleared).
Services are background daemons that provide system functions without user input, such as networking or web hosting. They typically start at boot and are managed by init systems like systemd using tools such as systemctl.
Apps are user-facing programs, either command-line or graphical, that run as one or more processes. They are installed via package managers (e.g., apt, dnf) or software centers.