Manual Pages  — CU

The options are as follows:

-a acu
	Set the acu.
-e
	Use even parity. If both -e and -o are given, then no parity is used (the default).
-h
	Echo characters locally (half-duplex mode).
-l line
	Specify the line to use. Either of the forms like cuau0 or /dev/cuau0 are permitted.
-o
	Use odd parity. If both -e and -o are given, then no parity is used (the default).
-s speed | speed
	Set the speed of the connection. The default is 9600.
-t
	Connect via a hard-wired connection to a host on a dial-up line.

Typed characters are normally transmitted directly to the remote machine (which does the echoing as well). A tilde (‘~’) appearing as the first character of a line is an escape signal; the following are recognized:

~^D or ~.
	Drop the connection and exit. Only the connection is dropped - the login session is not terminated.
~c [name]
	Change directory to name (no argument implies change to home directory).
~!	Escape to a shell (exiting the shell will return to cu).
~>	Copy file from local to remote. The cu utility prompts for the name of a local file to transmit.
~<	Copy file from remote to local. The cu utility prompts first for the name of the file to be sent, then for a command to be executed on the remote machine.
~p from [to]
	Send a file to a remote Unix host. This command causes the remote Unix system to run the following command string, sending it the from file:     stty -echo; cat > 'to'; stty echo If the to file is not specified, the from file name is used. This command is actually a Unix specific version of the ~> command.
~t from [to]
	Take a file from a remote Unix host. As in the ~p command, the to file defaults to the from file name if it is not specified. The remote host executes the following command string to send the file to cu:     cat 'from'; echo '' | tr '\012' '\01'
~|	Pipe the output from a remote command to a local Unix process. The command string sent to the local Unix system is processed by the shell.
~$	Pipe the output from a local Unix process to the remote host. The command string sent to the local Unix system is processed by the shell.
~C	Fork a child process on the local system to perform special protocols such as XMODEM. The child program will be run with the following arrangement of file descriptors: 0 <-> remote tty in 1 <-> remote tty out 2 <-> local tty stderr
~#	Send a BREAK to the remote system. For systems which do not support the necessary ioctl() call, the break is simulated by a sequence of line speed changes and DEL characters.
~s	Set a variable (see the discussion below).
~v	List all variables and their values (if set).
~^Z	Stop cu (only available with job control).
~^Y	Stop only the "local side" of cu (only available with job control); the "remote side" of cu, the side that displays output from the remote host, is left running.
~?	Get a summary of the tilde escapes.

When cu prompts for an argument, for example during setup of a file transfer, the line typed may be edited with the standard erase and kill characters. A null line in response to a prompt, or an interrupt, will abort the dialogue and return the user to the remote machine.

The cu utility guards against multiple users connecting to a remote system by opening modems and terminal lines with exclusive access, and by honoring the locking protocol used by uucico(8) ( ports/net/freebsd-uucp).

During file transfers cu provides a running count of the number of lines transferred. When using the ~> and ~< commands, the eofread and eofwrite variables are used to recognize end-of-file when reading, and specify end-of-file when writing (see below). File transfers normally depend on hardwareflow or tandem mode for flow control. If the remote system does not support hardwareflow or tandem mode, echocheck may be set to indicate that cu should synchronize with the remote system on the echo of each transmitted character.

When cu must dial a phone number to connect to a system, it will print various messages indicating its actions. The cu utility supports a variety of auto-call units and modems with the at capability in system descriptions.

Support for Ventel 212+ (ventel), Hayes AT-style (hayes), USRobotics Courier (courier), Telebit T3000 (t3000) and Racal-Vadic 831 (vadic) units is enabled by default.

Support for Bizcomp 1031[fw] (biz31[fw]), Bizcomp 1022[fw] (biz22[fw]), DEC DF0[23]-AC (df0[23]), DEC DN-11 (dn11) and Racal-Vadic 3451 (v3451) units can be added by recompiling cu with the appropriate defines.

Note that if support for both the Racal-Vadic 831 and 3451 is enabled, they are referred to as the v831 and v3451, respectively. If only one of the two is supported, it is referred to as vadic.

cu -s 115200 -l /dev/cuaU0