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cu [ -dh ] [ -e | -o ] [ -s speed ] -l line
cu [ -dh ] [ -e | -o ] systemname
cu calls up another system, or possibly a terminal. It manages an interactive conversation with possible transfers of ASCII files.
If phone-number is specified, it is the telephone number of the system to be dialed. Equal signs specify a pause for a secondary dial tone, and minus signs specify dialing delays of 4 seconds. If systemname is specified, it is the UUCP name of a the system to be dialed; in this case, cu will obtain an appropriate direct line or telephone number from /etc/uucp/Systems. Note: the systemname option should not be used in conjunction with the -l and -s options as cu will connect to the first available line for the system name specified, ignoring the requested line and speed. If neither phone-number nor systemname are specified, the -l line option must be provided; line specifies the device name to use.
After making the connection, cu runs as two processes: the transmit process reads data from the standard input and, except for lines beginning with ~, passes it to the remote system; the receive process accepts data from the remote system and, except for lines beginning with ~, passes it to the standard output. Normally, an automatic XON/XOFF protocol is used to control input from the remote so the buffer is not overrun.
A tilde (~) appearing as the first character of a line is an escape signal which directs cu to perform some special action. The transmit recognizes the following escape sequences:
For both ~%take and ~%put commands, as each block of the file is transferred, consecutive single digits are printed to the terminal.
The receive process normally copies data from the remote system to its standard output. Internally the program accomplishes this by initiating an output diversion to a file when a line from the remote begins with ~.
Data from the remote is diverted (or appended, if >> is used) to file on the local system. The trailing ~> marks the end of the diversion.
The use of ~%put requires stty.1v and cat.1v on the remote side. It also requires that the current erase and kill characters on the remote system be identical to these current control characters on the local system. Backslashes are inserted at appropriate places.
The use of ~%take requires the existence of echo.1v and cat.1v on the remote system. Also, tabs mode (see stty.1v should be set on the remote system if TAB characters are to be copied without expansion to SPACE characters.
When cu 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 executed by using ~~. In general, ~ executes the command on the original machine, ~~ executes the command on the next machine in the chain.
To dial a system whose telephone number is 9 201 555 1212 using 1200 baud (where dialtone is expected after the 9):
If the speed is not specified, ``Any'' is the default value.
To login to a system connected by a direct line:
or
To dial a system with the specific line and a specific speed:
To dial a system using a specific line associated with an auto dialer:
To use a system name:
Exit code is zero for normal exit, otherwise, 1.
The cu command does not do any integrity checking on data it transfers. Data fields with special cu characters may not be transmitted properly. Depending on the interconnection hardware, it may be necessary to use a `~.' to terminate the conversion even if stty 0 has been used. Non-printing characters are not dependably transmitted using either the ~%put or ~%take commands.
There is an artificial slowing of transmission by cu during the ~%put operation so that loss of data is unlikely.
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Created by unroff & hp-tools. © somebody (See intro for details). All Rights Reserved. Last modified 11/5/97