The question sounds like you might be trying to fit a square peg into a round hole. What are you trying to accomplish?
Generally speaking, the chef client would run as a daemon, not attached to a terminal, so the tty command wouldn't return anything meaningful; you'll probably just get "not a tty" or something like that. Of course you can manually start chef-client from your command line, but that would usually defeat the purpose.
Also, chef-client is a system administration tool that should generally run as user root, so you won't need sudo. People have made it run as another user, but you will run into all kinds of issues at every turn.
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