First, here’s a word about the UNIX way of keeping track of what programs are running.
A production UNIX server typically has a couple hundred programs running at once— particularly because each client that connects to the server usually causes a separate program to fire off (called forking) to serve the client. UNIX uses an internal process table that lists process numbers, the name of the processes, and other information.
Again, programs that are not interactive, yet are responsible for services are called daemons. All UNIX services, whether Telnet, HTTP, or FTP, run as daemons.
When looking at a process listing, ...