TTY(1)TTY(1)NAME
tty - get terminal name
SYNOPSIS
tty [ -s ]
DESCRIPTION
Tty prints the pathname of the user's terminal unless the -s (silent)
is given. In either case, the exit value is zero if the standard input
is a terminal and one if it is not.
DIAGNOSTICS
`not a tty' if the standard input file is not a terminal.
7th Edition April 29, 1985 TTY(1)