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System User's Guide: Communications and Networks

Exchanging Commands Between Local and Remote Systems

The Basic Networking Utilities (BNU) enable users to exchange commands between local and remote systems. The uux command runs commands on a remote system. The uupoll command controls the timing for command execution.

Using the uux Command

The uux command runs commands in the background on a remote system. The uux command uses system daemons and requires no interaction beyond the initial entry of the command.

The uux command gathers a queued file, or several files if batch processing is desired, from the designated systems. It then runs any user-specified commands contained in the sent files on the target remote system. (If a specified command does not exist on the remote system, the uux command does not execute. It returns a mail message about the problem.) If the command issued, such as the cat or diff command, produces some type of output, uux can be instructed to send that output to a specified file on any system.

Note: You can use the uux command on any system configured to run a specified command. However, policies at some sites may restrict the use of certain commands for security reasons. Some sites, for example, may only permit execution of the mail command.

Once the files are received on the remote system, the uuxqt daemon runs the specified command on that system. The uuxqt daemon periodically scans the remote system's public spool directory for files received in uux transmissions. The uuxqt daemon checks that data to be accessed by the sent files is present on the remote system. It also verifies that the sending system has permission to access the data. The uuxqt daemon then either executes the command or notifies the sending system that the command did not run.

For a demonstration of how the uux command can be applied, see "How to Transfer a File from Your Local System to a Remote System for Printing" .

Using the uupoll Command

The uupoll command starts the transmission of commands stored by the uux command in the local system's public spooling directory.

In normal operation, the uux command relies on the uucico daemon to periodically send files. Commands sent by one system are first transformed by the uux command into execute files that are stored in that system's public spooling directory. The uucico daemon scans the public directory. At regulated intervals, it sends any executable files to the target remote system.

The uupoll command creates a null job in the public directory and starts the uucico daemon. This stimulates the uucico scan earlier than is scheduled in the program.

Related Information

Using BNU Path Names.

Identifying Compatible Systems.

Communicating Between Local and Remote Systems.

Exchanging Files Between Local and Remote Systems.

Reporting the Status of Command and File Exchanges.


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