Telnet Daemon Overview

Purpose

The Telnet daemon is a server-side implementation of the TELNET protocol, a connection-oriented client-server protocol used for remote logins. It enables you to connect to a Symbian platform device through a Telnet client and run Z Shell (Zsh) commands. The daemon is an interface between the remote Telnet client and the Zsh running on the Symbian platform device.

The Telnet daemon enables you to run the Zsh commands to perform the following tasks from a remote Telnet client:

  • Start an application

  • List all the processes running on the device

  • Stream the standard output (STDOUT) and error output (STDERR) of a process running on the device to the remote PC.

Besides running the Zsh commands on a Symbian platform device, the Telnet daemon also enables you to perform the following tasks, which are not supported by Zsh:

  • Install and uninstall an SIS package

  • Terminate a process

Key concepts

Telnet client

A Telnet client is an application used to communicate with the Telnet daemon running on a remote host (Symbian platform device). It enables PC users to connect to a remote host over an IP-based link.

Z Shell

Z Shell (Zsh) is a UNIX command interpreter ported to Symbian platform. It provides a Unix-like environment on a Symbian platform device to run basic UNIX commands. For more information on Z Shell and the supported commands, refer to Symbian OS Library >> Symbian OS Tools And Utilities >> Text Shell (Zsh) and Telnet Daemon.

How the Telnet daemon works

The following illustration shows how remote PCs using a Telnet client send requests to the Telnet daemon running on the Symbian platform device.

Remote PCs communicating with the Symbia...


Remote PCs communicating with the Symbian platform device over an IP-based network.

Typical uses

Installing and uninstalling an SIS package

You can install or uninstall an SIS package on the Symbian platform device. To install or uninstall an SIS package, the SIS file must be transferred to the device using the FTP daemon. When the SIS file is available on the Symbian platform device, use the following Telnet commands to install and uninstall:

> test_install <sis_file>

> test_uninstall <UID_of_the_application>

Starting an application

You can request the Telnet daemon to start a console-based application. To start an application, use the following command:

> <application_name>

Alternatively, you can use the command, command. For more information, refer to Symbian OS Library >> Symbian OS Tools And Utilities >> Text Shell (Zsh) and Telnet Daemon >> Reference >> Zsh Command Syntax

Terminating a process

You can send a request to terminate an active process. To terminate a process, you must know its PID (Process ID). To display all the active processes, run the following command:

> ps -f

When you know the PID of the process you want to terminate, use the following command:

> test_kill <PID>