Shell Programming and Scripting

hi there,
can somebody give me a definition for daemons, or example what are they !!
and what the use for?

i've done some research and all what i found is /etc/...
or /usr/bin/...

and i haven't quietly got the concept.

any ideas !!
Thanks.

This may not be 100% correct but I think pretty close and simple, but daemons are programs that continue to run on your system at all time.... like crond is a daemon for crontab... do a ps -ef | grep root on a box and most of those programs running will be daemons..

Ive got output:

root 2 0 0 Jun16 ? 00:00:00 [kthreadd]
root 3 2 0 Jun16 ? 00:00:00 [migration/0]
root 4 2 0 Jun16 ? 00:00:00 [ksoftirqd/0]
root 5 2 0 Jun16 ? 00:00:00 [watchdog/0]
root 6 2 0 Jun16 ? 00:00:01 [events/0]
root 7 2 0 Jun16 ? 00:00:00 [khelper]
root 49 2 0 Jun16 ? 00:00:00 [kblockd/0]
root 50 2 0 Jun16 ? 00:00:00 [kacpid]

root 2359 1 0 Jun16 ? 00:00:00 /usr/sbin/smartd -q never
root 2365 1 0 Jun16 tty2 00:00:00 /sbin/mingetty tty2
root 2366 1 0 Jun16 tty3 00:00:00 /sbin/mingetty tty3
root 2367 1 0 Jun16 tty4 00:00:00 /sbin/mingetty tty4
root 2368 1 0 Jun16 tty5 00:00:00 /sbin/mingetty tty5
root 2369 1 0 Jun16 tty6 00:00:00 /sbin/mingetty tty6


is all of them called daemons or just the ones that running from
/sbin/...
do we call them daemon just for the ones that runs for root or also for users?

Thanks.

The ones with the question marks are the daemons. That is very definition of daemon to the kernel... no controlling tty.

Thanks guys that was really helpful.

check this if you want to read further