V4/man/man1/tty.1

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.th TTY I 3/15/72
.sh NAME
tty \*- get typewriter name
.sh SYNOPSIS
.bd tty
.sh DESCRIPTION
.it Tty
gives the name of the user's typewriter
in the form `tty\fIn\fR' for
\fIn\fR
a digit or letter.  The actual path
name is then `/dev/tty\fIn\fR'.
.sh DIAGNOSTICS
`not a tty' if the standard input file is not a typewriter.
.sh BUGS