.TH CU 1C
.UC
.SH NAME
cu \- call UNIX
.SH SYNOPSIS
.B cu
telno
[
.B \-p
]
[
.B \-t
]
[
.BI \- n
[
.B \-s
speed ]
[
.B \-a
acu ]
[
.B \-l
line ]
[
.B \-b
]
[
.B \-h
]
.SH DESCRIPTION
.I Cu
calls up another UNIX system,
a terminal,
or possibly a non-UNIX system.
It manages an interactive conversation with possible
transfers of text files.
.I Telno
is the telephone number,
with minus signs at appropriate places for delays.
If the 
.B \-p
option is specified, parity bits are stripped on both send and receive,
otherwise the data path from the terminal to the remote system
is a full 8 bits.
The
.BR \-t ""
flag is used to dial out to a terminal.
.I Speed
gives the transmission speed (110, 134, 150, 300, 1200);
300 is the default value.
.PP
The
.B \-a
and
.B \-l
values may be used to
specify pathnames
for the ACU and communications line devices.
They can be used to override the following
built-in choices:
.PP
.BR \-a " /dev/cua0"
.BR \-l " /dev/cul0"
.PP
The
.BI \- n
option, where
.I n
is a single digit,
changes the last character of the ACU and communications line to
.IR n .
It is an abbreviation for
.BI "\-a /dev/cua" n " \-l /dev/cul" n .
.PP
The
.BR \-b
flag specifies that nulls are to be turned into deletes (ascii \\177).
This allows the break key (and also control-shift-@) to send an interrupt.
.PP
Finally, the
.B \-h
option causes local echo of all characters typed, for calling into
a half-duplex system.
.PP
After making the connection,
.I cu
runs as two processes:
the
.I send
process reads the standard input and
passes most of it to the remote system;
the
.I receive
process reads from the remote system and passes
most data to the standard output.
Lines beginning with `~' have special meanings.
.PP
The
.I send
process interprets the following:
.TP 18
~\|\fB.\|
terminate the conversation.
.br
.ns
.TP 18
~EOT
terminate the conversation
.TP 18
~<file
send the contents of
.I file
to the remote system,
as though typed at the terminal.
.TP 18
\~^Z
suspend the cu process.
Note that the control-Z must be followed by a newline.
.TP 18
\~#
sends a break.
.TP 18
~!
invoke an interactive shell on the local system.
.TP 18
~!cmd ...
run the command on the local system
(via
.BR "sh \-c" ")."
.TP 18
~$cmd ...
run the command locally and send its output
to the remote system.
.TP 18
~%take from [to]
copy file `from' (on the remote system)
to file `to' on the local system.
If `to' is omitted,
the `from' name is used both places.
.TP 18
~%put from [to]
copy file `from' (on local system)
to file `to' on remote system.
If `to' is omitted, the `from' name is used both places.
.TP 18
~:
during an output diversion, this toggles whether the operation of
.I cu
will be silent, i.e., whether information received from the foreign
system will be written to the standard output.
This allows a ``progress report'' during long transfers.
.TP 18
~~\fB\|.\|.\|.\fP
send
the line `~\|.\|.\|.'.
.PP
Both the
.I send
and
.I receive
processes handles output diversions of the following form:
.PP
\&~>[>][:]file
.br
zero or more lines to be written to file
.br
\&~>
.PP
In any case, output is diverted (or appended, if `>>' used) to the file.
If `:' is used,
the diversion is
.I silent,
i.e., it is written only to the file.
If `:' is omitted,
output is written both to the file and to the standard output.
The trailing `~>' terminates the diversion.
.PP
The use of
.B  ~%put
requires
.I stty
and
.I cat
on the remote side.
It also requires that the
current erase and kill characters on the remote
system be identical to the current ones on the local system.
Backslashes are inserted at appropriate places.
.PP
The use of
.B  ~%take
requires the existence of
.I echo
and
.I tee
on the remote system.
Also,
.B "stty tabs"
mode is required on the remote system if
tabs are to be copied without expansion.
.SH FILES
/dev/cua0
.br
/dev/cul0
.br
/dev/null
.br
/usr/spool/uucp/LCK..cu[al][0-7]
.SH "SEE ALSO"
dn(4), tty(4)
.SH DIAGNOSTICS
Exit code is
zero for normal exit,
nonzero (various values) otherwise.
.SH BUGS
Only
.IR Mail (1)
uses syntax anything like the syntax of
.I cu.