wireshark is not a service, you just run it as a client program. A simple thing to get confused with though is that, normally, the "wireshark" rpm is actually *not* wireshark, but the common libraries for it and the *TEXT* interface to it, tshark. if you want the super swishy singy dancy gui for it, then also install "wireshark-gnome".
note that if you do have redhat 8.0 then you will actually have the older version of the program, when it was called ethereal, but if at all possible you shouldn't use such an old distro, use something newer like fedora (as the modern day equivalent of redhat) or ubuntu for example.
And it's "Linux" not "Linus". Linus Torvalds is the guy that started it. I've no how how so so many people call it by the wrong name.