Wireshark is used for Passive Network Analysis to diagnose network issues. tshark provides a CLI for this tool. This guide provides examples and direction on how to use tshark and pitfalls to avoid. This is a living, breathing guide. If you’d like to contribute, fork me on GitHub!
Wireshark documentation is sufficient to document a feature’s existance, but not its usage. It’s a reference, not a guide.
If you have a Wireshark question, there are mayn good resources like the Official Documentation, the manpages, or you can ask a question on Wireshark Forums.