Checking what services are running

Several tools are available. We will just scratch the surface here; if you want to dig deeper you can use the 'man' command to read the system's reference, i.e. //man ps//

ps

Ps is there on allmost all unix oses. But you may find that they may vary in usage. We will use grep to filter the content we are interested in. root@yourserver:/# ps -eaf |grep cit root 16824 1 0 00:30 ? 00:00:00 /usr/sbin/citserver -d -x3 -lmail -t/dev/null citadel 16825 16824 0 00:30 ? 00:00:07 /usr/sbin/citserver -d -x3 -lmail -t/dev/null root 27303 27559 0 21:47 ttyp4 00:00:00 grep cit two citserver processes are running here. Thats fine because of citadel uses one process to monitor that its main process stays available to you.

pstree

this is not available on all oses. But as it gives a nice output here what its looking like: root@yourserver:/# pstree -p init(1)-+-citserver(16824)---citserver(16825)-+-{citserver}(16831) | |-{citserver}(16832)

        |                                     |-{citserver}(16832)
        |                                     |-{citserver}(16833)
        |                                     |-{citserver}(16833)
        |                                     |-{citserver}(16834)
        |                                     |-{citserver}(16834)
        |                                     |-{citserver}(16835)
        |                                     |-{citserver}(16835)
        |                                     `-{citserver}(16836)
        |                                     `-{citserver}(16836)
        |-cron(3464)
        |-cron(3464)
        |-getty(3563)
        |-getty(3563)
        |-getty(3564)
        |-getty(3564)
        |-webserver(27328)---webserver(27329)-+-{webserver}(27334)
        |-webserver(27328)---webserver(27329)-+-{webserver}(27334)
        |                                     |-{webserver}(27335)
        |                                     |-{webserver}(27335)
        |                                     |-{webserver}(27336)
        |                                     |-{webserver}(27336)
        |                                     |-{webserver}(27337)
        |                                     |-{webserver}(27337)
        |                                     |-{webserver}(27338)
        |                                     |-{webserver}(27338)
        |                                     `-{webserver}(27339)
        |                                     `-{webserver}(27339)

which shows you the watcher processes and, as its child the worker. 
Here we have one running webcit, if you have enabled ssl, you will find another branch.
 top / prstat 
Keeps an interactive display. It can sort by Cpu or Memory usage.