.TH VT 1 
.SH NAME
vt \- emulate a VT-100 or VT-220 terminal
.SH SYNOPSIS
.B vt
[
.B -2sa
]
.SH DESCRIPTION
.I Vt
replaces a rio window with a fresh instance of the shell
.IR rc (1)
running within an emulation of a DEC VT-100 terminal.
The
.B -2
and
.B -a
options configure
.I vt
to emulate a VT-220 and Ansi terminal respectively.
The
.B -s
options forces a saner color scheme, i.e, black text on white
background.
.PP
The right button has a menu with the following entries to provide
the sort of character processing expected by non-Plan 9 systems:
.TF cooked
.TP
.B 24x80
Resize the
.I vt
window to hold 24 rows of 80 columns.
.TP
.B crnl
Print a newline (linefeed) character after receiving a carriage return from the host.
.TP
.B cr
Do not print a newline after carriage return.
.TP
.B nlcr
Print a carriage return after receiving a newline from the host.
.TP
.B nl
Do not print a carriage return after newline.
.TP
.B raw
Enter raw (no echo, no interpretation) character mode for input.
.TP
.B cooked
Leave raw mode.
.TP
.B exit
Exits
.IR vt .
.PD
.PP
The middle button has a menu with the following entries:
.TF right_key
.TP
.B backup
Move the display back one screenful.
.TP
.B forward
Move the display forward one screenful.
(These are a poor substitute for a scroll bar.)
.TP
.B reset
Display the last screenful; the same as going
.B forward
to the end.
.TP
.B clear
Clear the screen.  Previous contents can be recovered using
.BR backup .
.TP
.B send
Send the contents of the
.B rio
snarf buffer, just as
.B send
in the
.B rio
menu.
.TP
.B scroll
Make new lines visible as they appear at the bottom.
.TP
.B page
When the page fills, pause and wait for a character to be typed before proceeding.
The down arrow key advances a page without sending the character to the host.
.PD
.PP
To exit
.IR vt ,
exit its
.B rc
session by, for example, typing EOT (control-D).
.SH SOURCE
.B /sys/src/cmd/vt
.SH BUGS
.PP
This program is used only for communicating with foreign systems, so it is not
as rich an emulation as its equivalent in other environments.
.PP
Use care in setting raw and newline modes when connecting to Unix systems
via
.IR con .
It may also be necessary to set the emulator into raw mode.