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 is present on almost all unix variants. 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. Older versions of Citadel may have a second one as a monitor process.
This is not available on all oses. If you have it, here is what it might look 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)
This 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.
These programs maintain an interactive display sorted by CPU or memory usage.