osx man page for tty

TTY(1)							    BSD General Commands Manual 						    TTY(1)

NAME
     tty -- return user's terminal name

SYNOPSIS
     tty [-s]

DESCRIPTION
     The tty utility writes the name of the terminal attached to standard input to standard output.  The name that is written is the string
     returned by ttyname(3).  If the standard input is not a terminal, the message ``not a tty'' is written.  The options are as follows:

     -s      Do not write the terminal name; only the exit status is affected when this option is specified.  The -s option is deprecated in favor
	     of the ``test -t 0'' command.

EXIT STATUS
     The tty utility exits 0 if the standard input is a terminal, 1 if the standard input is not a terminal, and >1 if an error occurs.

SEE ALSO
     test(1), ttyname(3)

STANDARDS
     The tty utility is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.

HISTORY
     A tty command appeared in Version 1 AT&T UNIX.

BSD
								   June 6, 1993 							       BSD