Using UUCP and dialup commands

Transferring files between UNIX systems

Transferring copies of binary and text files between remote UUCP systems can be achieved using the uucp(C) and uuto(C) commands. There are advantages and disadvantages to each. The uucp command gives you great flexibility in specifying where on the remote system the transferred file is to be placed, but the uucp command line can be complicated. The uuto command, on the other hand, is easy to use, but restricts where you can place the file on the remote system. In addition, retrieving a file sent with uuto is slightly more complicated than retrieving a file sent with uucp.

Before you can copy files to remote sites with uucp, you must verify that:

Your site knows how to call the remote site.
The files that you want to send have read permission set for others.
The directory that contains the file that you want to send has read and execute permissions set for others. This allows the directory to be searched.
Your computer has write permission in the directory on the remote site to which you want to copy the file.

You must be sure that your computer ``talks'' to the site with which you want to communicate. The uuname command gives you this information. Entering uuname with no options lists the UUCP sites your computer talks to directly. For example:

$uuname

kate


rachel


$

Entering uuname with the -l option causes the name of your computer to be displayed. For example:

$uuname -l
jane $

This tells you the name by which your computer is known on the UUCP network.

Note that you might be able to communicate with a site that does not show up in a uuname listing. This is possible because UUCP sites are often ``chained together''. So if you know that a site to which you want to transfer files communicates with a site your system communicates with, you can send files to the first site through the second.

For example, say your system (called jane) knows how to communicate with two other systems (called kate and rachel, as in the previous example). If kate has connection to a fourth system, alice, you can send files to alice via kate by typing kate!alice to specify a path. This is equivalent to the mail addressing technique described in the Mail and Messaging Guide.

Finally, you must verify that your computer has write permission on the directory on the remote site to which you want to transfer files. Each remote UUCP site has a /usr/lib/uucp/Permissions file. This file specifies the directories on that site from which your computer can read and to which your computer can write. You can only send a file to a directory on a remote site if your computer has write permissions on that directory, as specified on the remote site's /usr/lib/uucp/Permissions file.

In order to copy a file to a remote UUCP site, the file must have read permission set for others and the directory that contains the file must have read and execute permissions set for others. Use the l command to examine the file's permissions and the l -d command to examine the directory's permissions. If the permissions are not correct and you own the file, enter the following commands to set the correct permissions:

chmod o+r filename
chmod o+rx directory

(See chmod(C) for details.) By default, most UUCP sites permit calling-in computers to write to their /usr/spool/uucppublic directory, which is available on most UUCP systems as a general purpose file transfer directory. Since there is no way to find out which directories your computer can write to on the remote site, other than contacting somebody at the site, the safest thing to do when making a UUCP transfer is to write to /usr/spool/uucppublic. The procedure for doing this is outlined below.