can I install only tshark?
I mean, without installing wireshark.
you may be able to do that with portable app
...IF the operating system is Windows. If you're installing a package that's part of some Linux distribution's packaging system, there might be multiple packages, one of which installs the non-GUI parts of Wireshark, and another of which installs the Wireshark GUI app, but that depends on which distribution, as do the names of the packages if there are multiple packages. The package the Wireshark developers offer for macOS doesn't offer such an option.
Operating system?
...because the answer to the question, and to the subsequent question "how do I do that?", depends on the operating system, unless you're building Wireshark from source, because it depends on how Wireshark is packaged.