1.\" $OpenBSD: cu.1,v 1.15 2015/05/18 09:35:05 nicm Exp $ 2.\" 3.\" Copyright (c) 1980, 1990, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.Dd $Mdocdate: May 18 2015 $ 31.Dt CU 1 32.Os 33.Sh NAME 34.Nm cu 35.Nd serial terminal emulator 36.Sh SYNOPSIS 37.Nm 38.Op Fl d 39.Op Fl l Ar line 40.Op Fl s Ar speed | Fl Ar speed 41.Nm 42.Op Ar host 43.Sh DESCRIPTION 44.Nm 45is used to connect to another system over a serial link. 46In the era before modern networks, it was typically used to 47connect to a modem in order to dial in to a remote host. 48It is now frequently used for tasks such as attaching to the 49serial console of another machine for administrative or 50debugging purposes. 51.Pp 52The options are as follows: 53.Bl -tag -width 4n 54.It Fl d 55Specify that the line is directly connected and 56.Nm 57should not allow the driver to block waiting for a carrier to be detected. 58.It Fl l Ar line 59Specify the line to use. 60Either of the forms like 61.Pa cua00 62or 63.Pa /dev/cua00 64are permitted. 65The default is 66.Pa /dev/cua00 . 67See 68.Xr cua 4 69for information on terminal devices. 70Users in group 71.Dq dialer 72are permitted to use 73.Xr cua 4 74devices by default. 75.It Fl s Ar speed | Fl Ar speed 76Set the speed of the connection. 77The default is 9600. 78.El 79.Pp 80If 81.Ar host 82is given, 83.Nm 84uses the 85.Xr remote 5 86database to retrieve the 87.Sy dc Pq directly connected , 88.Sy dv Pq device 89and 90.Sy br Pq baud rate 91capabilities for that host. 92The 93.Nm 94utility ignores other capabilities found in that database. 95.Pp 96Typed characters are normally transmitted directly to the remote 97machine (which does the echoing as well). 98A tilde 99.Pq Ql ~ 100appearing as the first character of a line is an escape signal; the 101following are recognized: 102.Bl -tag -offset indent -width Fl 103.It Ic ~^D No or Ic ~. 104Drop the connection and exit. 105Only the connection is dropped \(en the login session is not terminated. 106.It Ic ~\*(Gt 107Copy file from local to remote. 108.Nm 109prompts for the name of a local file to transmit. 110.It Ic ~$ 111Pipe the output from a local 112.Ux 113process to the remote host. 114The command string sent to the local 115.Ux 116system is processed by the shell. 117.It Ic ~# 118Send a 119.Dv BREAK 120to the remote system. 121.It Ic ~^Z 122Stop 123.Nm 124(only available with job control). 125.It Ic ~C 126Fork a child process on the local system to perform special protocols 127such as XMODEM. 128The child program will be run with the following arrangement of 129file descriptors: 130.Bd -literal -offset indent 1310 \*(Lt-\*(Gt remote tty in 1321 \*(Lt-\*(Gt remote tty out 1332 \*(Lt-\*(Gt local tty stderr 134.Ed 135.It Ic ~D 136Deassert the data terminal ready (DTR) line briefly. 137.It Ic ~R 138Record all output from the remote system to a file. 139If the given file already exists, it is appended to. 140If no file is specified, any existing recording is stopped. 141.It Ic ~S 142Change the speed of the connection. 143.It Ic ~X 144Send a file with the XMODEM protocol. 145.It Ic ~? 146Get a summary of the tilde escapes. 147.El 148.Pp 149When 150.Nm 151prompts for an argument, for example during setup of a file transfer, 152the line typed may be edited with the standard erase and kill characters. 153A null line in response to a prompt, or an interrupt, will abort the 154dialogue and return the user to the remote machine. 155.Pp 156.Nm 157guards against multiple users connecting to a remote system by opening 158modems and terminal lines with exclusive access. 159.Sh ENVIRONMENT 160.Bl -tag -width REMOTEXXX 161.It Ev HOST 162The default value for 163.Ar host 164if none is specified via the command line. 165.It Ev REMOTE 166A system description, or an absolute path to a 167.Xr remote 5 168system description database. 169.El 170.Sh FILES 171.Bl -tag -width /etc/remote 172.It Pa /etc/remote 173host description file 174.El 175.Sh EXIT STATUS 176.Ex -std cu 177.Sh SEE ALSO 178.Xr remote 5 179.Sh HISTORY 180The 181.Nm 182command appeared in 183.Bx 4.2 . 184This version was written for 185.Ox 5.4 186by Nicholas Marriott. 187