Using UUCP and dialup commands

Using two computers at the same time

The cu (call up) command makes your local computer call a remote computer and allows you to be logged in on both systems simultaneously. The remote computer does not have to be a UNIX system.

If the remote computer is a UNIX system, cu allows you to move back and forth between the two computers, transferring files and executing commands on both. Note that cu only allows you to transfer text files. You cannot transfer binary files with cu. To transfer binary files to a remote UNIX system, use uucp.

The format of the cu command is:

cu [options] target

The target argument can take one of four forms:

phone number: This is the number of the remote computer to which you want to connect. You can embed equal signs, which represent secondary dial tones, and dashes, which represent four-second delays, in the telephone number. A sample telephone number might be 4085551212--100. This number contains an area code and number, two dashes for an eight second delay, and an extension.
system-name: This is the name of a system that is listed in the /usr/lib/uucp/Systems file. The cu command obtains the telephone number and the baud rate of system-name from this file. The -s, -n, and -l options should not be used with system-name. To see the list of computers in the Systems file, enter uuname.
-l line: This is the device name of the serial line connected to the remote computer. It has the form ttyXX, where XX is the number of a serial line.
-l line dir: This connects directly with the serial line instead of making a telephone connection.

Once the connection is made, if the remote computer is a UNIX system, you are presented with a login prompt. Log in as you would if you were connected locally. When you finish working on the remote computer, log out as you would if you were connected locally, then terminate the cu connection by entering a tilde followed by a period (~.). (The tilde, when entered at the beginning of a line, is an escape character that tells cu to process the next piece of text itself, instead of sending it to the remote computer. The period is the cu command to terminate the session. Other commands are available.)

As an example, suppose that you want to log in to a remote UNIX computer via the telephone lines. Suppose also that the remote computer's number is 555-1212. To connect to the remote computer, enter the following command:

cu -s1200 5551212

The -s1200 option causes cu to use a 1200 baud dialer. If the -s option is not specified, cu uses the first available dialer at the speed specified in the /usr/lib/uucp/Devices file.

When the remote UNIX system answers the call, cu notifies you that the connection has been made by displaying the following message:

   Connected

Next, you are prompted for your login:

   login:

Enter your login and password. Once you enter this information, you can use this computer as if you were logged in locally. When you are finished, log out and then enter:

~.

This terminates the cu session.