CU(1C) CU(1C)
NAME
cu - call UNIX
SYNOPSIS
cu telno [ -t ] [ -s speed ] [ -a acu ] [ -l line ]
DESCRIPTION
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. Telno is the telephone number, with minus signs at appropriate places for delays. The -t flag is used to dial out to a
terminal. Speed gives the transmission speed (110, 134, 150, 300, 1200); 300 is the default value.
The -a and -l values may be used to specify pathnames for the ACU and communications line devices. They can be used to override the fol-
lowing built-in choices:
-a /dev/cua0 -l /dev/cul0
After making the connection, cu runs as two processes: the send process reads the standard input and passes most of it to the remote sys-
tem; the receive process reads from the remote system and passes most data to the standard output. Lines beginning with `~' have special
meanings.
The send process interprets the following:
~. terminate the conversation.
~EOT terminate the conversation
~<file send the contents of file to the remote system, as though typed at the terminal.
~! invoke an interactive shell on the local system.
~!cmd ... run the command on the local system (via sh -c).
~$cmd ... run the command locally and send its output to the remote system.
~%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.
~%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.
~~... send the line `~...'.
The receive process handles output diversions of the following form:
~>[>][:]file
zero or more lines to be written to file
~>
In any case, output is diverted (or appended, if `>>' used) to the file. If `:' is used, the diversion is 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 diver-
sion.
The use of ~%put requires stty and cat on the remote side. It also requires that the current erase and kill characters on the remote sys-
tem be identical to the current ones on the local system. Backslashes are inserted at appropriate places.
The use of ~%take requires the existence of echo and tee on the remote system. Also, stty tabs mode is required on the remote system if
tabs are to be copied without expansion.
FILES
/dev/cua0
/dev/cul0
/dev/null
SEE ALSO
dn(4), tty(4)
DIAGNOSTICS
Exit code is zero for normal exit, nonzero (various values) otherwise.
BUGS
The syntax is unique.
CU(1C)
Check Out this Related Man Page
cu(1) General Commands Manual cu(1)
NAME
cu - call another (UNIX) system; terminal emulator
SYNOPSIS
speed] line] level] [telno|systemname
UNIX Standard Syntax
speed] line] [telno|systemname
DESCRIPTION
calls up another system, which is usually a UNIX operating system, but can be a terminal or a non-UNIX operating system. manages all
interaction between systems, including possible transfers of ASCII files.
Options
recognizes the following options and command-line arguments:
Specify the transmission speed
(110, 150, 300, 600, 1200, 2400, 3600, 4800, 7200, 9600, 19200). The default value is 300.
Specify a device name to use as the communication line.
This can be used to override searching for the first available line having the right speed. When the option is used
without the option, the speed of a line is obtained from file When the and options are used simultaneously, searches
to determine whether the requested speed for the requested line is available. If so, the connection is made at the
requested speed; otherwise, an error message is printed and the call is not made. The specified device is usually a
directly connected asynchronous line (such as In this case, a telephone number is not required, but the string can be
used to specify that a dialer is not required. If the specified device is associated with an auto-dialer, a tele-
phone number must be provided.
Emulate local echo,
supporting calls to other computer systems that expect terminals to be set to half-duplex mode.
Use ENQ/ACK handshake (remote system sends ENQ,
sends ACK.)
Used when dialing an ASCII terminal that has been set to auto-answer. Appropriate mapping of carriage-return to carriage-return-
line-feed pairs is set.
Print diagnostic traces.
level is a number from 0-9, where higher levels produce more detail in the diagnostic messages.
(UNIX Standard only, see
standards(5).) Print diagnostic traces. The level is always 9.
Generate even (odd) parity for data sent to the remote.
Specify a direct line that has modem controls.
Modem controls are ignored by
Cause the telephone number that
dials to be requested interactively from the user rather than taking it from the command line.
telno When using an automatic dialer, telno is the telephone number, with equal signs for secondary dial tone or minus
signs for delays appropriately placed in the telno string.
systemname A UUCP system name can be used instead of a telephone number (see uucp(1)); in this case, obtains an appropriate
direct line or telephone number from (including appropriate baud rate). dials each telephone number or direct line
for systemname in the file until a connection is made or all the entries are tried.
Using ensures that uses the line specified by the option.
After making the connection, runs as two processes:
o transmit process reads data from the standard input and, except for lines beginning with passes it to the remote system;
o receive process accepts data from the remote system and, except for lines beginning with passes it to the standard output.
Normally, an automatic DC3/DC1 protocol is used to control input from the remote to ensure that the buffer is not overrun. "Prompt hand-
shaking" can be used to control transfer of ASCII files to systems that have no type-ahead capability but require data to be sent only
after a prompt is given. This is described in detail below. Lines beginning with have special meanings.
Transmit Process Commands
The transmit process interprets the following commands:
Terminate the conversation.
On hard-wired lines, sends several EOF characters to log out the session, whereas suppresses the EOF sequence. In
general the remote hard-wired machine is unaware of the disconnect if is used. On dial-up connections, and do not
differ.
Escape to an interactive shell on the local system.
Run cmd on the local system (via
Similar to but kill the receive process, restarting it upon return from the shell. This is useful for invoking sub-processes
that read from the communication line where the receive process would otherwise compete for input.
Run cmd on the local system (via and kill the receive process, restarting it later.
Pipe incoming data from the remote system through the standard input to
cmd on the local system. To terminate, reset with either a or command.
Resets the receive process following a
command.
Run cmd locally and send its output to the remote system.
Change the directory on the local system.
Note: causes the command to be run by a sub-shell, causing a return to the current directory upon completion.
Copy file remote_source_file from the remote system to file local_destination_file on the local system. If local_destina-
tion_file is not specified, the remote_source_file argument is used in both places.
Copy file local_source_file on local system to file remote_destination_file on remote system. If remote_destination_file is
not specified, the local_source_file argument is used in both places.
Send the line to the remote system. If you use on the remote system to access a third remote system, send to cause the second
remote to exit.
Transmit a BREAK to the remote system.
Toggle between DC3/DC1 input control protocol and no input control. This is useful if the remote system does not respond properly
to the DC3 and DC1 characters.
Send the contents of the local file to the remote system using
prompt handshaking. The specified file is read one line at a time, and each line is sent to the remote system when
the prompt sequence is received. If no prompt is received by the time the prompt timeout occurs, the line is sent
anyway. If the timeout is set to 0 seconds, or if the first character in the prompt sequence is a null character
(^@), the handshake always appears to be satisfied immediately, regardless of whether or not the remote system gener-
ates a prompt. This capability is intended mainly to facilitate transfer of ASCII files from HP-UX to an HP 3000
system running MPE. This is usually accomplished by running the MPE utility and giving the command and then running
the input diversion to send the file to which saves it in destfile. This facility might be useful with other systems
also, such as an HP 1000 running RTE.
Specify the number of seconds to wait for a prompt before giving up.
The default is 2 seconds. Specifying a timeout of 0 seconds disables handshaking; that is, handshake appears to com-
plete immediately.
Set the handshake prompt to the characters
xy. The default is DC1. The prompt can be any one or two characters. To specify a control character for x or y,
use the Ctrl-X form where a circumflex (ASCII 94) precedes the character, as in A null character can be specified
with ^@. (A null first character in the prompt implies a "null" prompt, which always appears to be satisfied.) A
circumflex is specified by
Divert output from the remote system to the specified file until another
command is given. When an output diversion is active, typing terminates it, whereas anotherfile terminates it and
begins a new one. The output diversion remains active through a subshell, but unpredictable results can occur if
input/output diversions are intermixed with or The command appends to the named file. Note that these commands,
which are interpreted by the transmit process, are unrelated to the commands described below, which are interpreted
by the receive process.
Suspend the session. susp is the suspend character set in the terminal when was invoked (usually -- see stty(1)). As in all
other lines starting with tilde, a line must be terminated by pressing
Receive Process
The receive process normally copies data from the remote system to its standard output. A line from the remote that begins with initiates
an output diversion to a file. The complete sequence is:
zero or more lines to be written to file
Data from the remote is diverted (or appended, if is used) to file. The trailing terminates the diversion.
The use of requires stty(1) and cat(1) on the remote side. It also requires that the current erase and kill characters on the remote sys-
tem be identical to the current ones on the local system. Backslashes are inserted at appropriate places.
The use of requires that the remote system support the and commands (see echo(1) and cat(1). Also, mode should be set on the remote system
if tabs are being copied without expansion. When connecting to a machine that uses the eighth bit as a parity bit, mode should be set on
the local system.
When is used on system X to connect to system Y and subsequently used on system Y to connect to system Z, commands on system Y can be exe-
cuted if is used. For example, using the keyboard on system X, can be executed on Z, X, and Y as follows where lines 1, 3, and 5 are key-
board commands, and lines 2, 4, and 6 are system responses:
In general, causes the command to be executed on the original machine; causes the command to be executed on the next machine in the chain.
EXTERNAL INFLUENCES
For information about the UNIX Standard environment, see standards(5).
Environment Variables
determines the language in which messages are displayed.
If is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of If any internationalization variable
contains an invalid setting, behaves as if all internationalization variables are set to "C". See environ(5).
International Code Set Support
Single- and multi-byte character code sets are supported.
DIAGNOSTICS
Exit code is zero for normal exit; non-zero (various values) otherwise.
EXAMPLES
To dial a system whose number is 9 201 555 1212 using 1200 baud:
If the speed is not specified, 300 is the default value.
To log in on a system connected by a direct line:
To dial a system with the specific line and a specific speed:
To dial a system using a specific line:
To use a system name
To connect directly to a modem:
WARNINGS
buffers input internally.
AUTHOR
was developed by AT&T and HP.
FILES
SEE ALSO
cat(1), ct(1), echo(1), stty(1), uname(1), uucp(1), uuname(1), standards(5).
STANDARDS CONFORMANCE
cu(1)