daemonDaemon is a UNIX term for a program which is always running and listening for requests for a program or service, to fulfill which it spawns other processes Daemons are similar to a PC's TSRs, programs which remain in memory until called upon to perform a specific task. Common types of daemons are utilities that handle FTP, gopher, telnet or Web services.
UNIX systems run many daemons, chiefly to handle requests for services from other hosts on a network. Examples are cron (local timed command execution), rshd (remote command execution), rlogind and telnetd (remote login), ftpd, nfsd (file transfer), lpd (printing).