Hey there @mindblender! Welcome back to the community! I can confirm ushell.bat does ship with 5.5 on Windows with the EGS build. However it seems for both Linux and MacOS only source builds come with it. So if possible, you may need to run a source build and verify if the utility is there.
https://github.com/EpicGames/UnrealEngine/tree/release/Engine/Extras/ushell