Command Client
Last updated at 2005/05/10 18:13:31 PDT by Temporal

The Evlan command client is a Java program which can be used to connect to the Evlan virtual machine to issue commands. Once you have the Evlan virtual machine running on your platform, getting the client running is easy.

First, you must have Java 5 (aka Java 1.5 or even "Java 2 version 5") installed.

If you downloaded a source code package, run the following commands in the evlan-client-0.3.3 directory to compile the client:

javac *.java
jar cmf manifest.txt evlan-client.jar *.class

This will produce the evlan-client jar file. If you downloaded the binary distribution, you already have this file.

To run evlan-client, just double-click on it. Or, if your GUI doesn't allow that, type:

java -jar evlan-client.jar

You will be asked for various connection information when the client starts. Choose this to match what you wrote in the VM's config file. If you did not edit the config file, the default parameters should be correct, except that you must disable SSL mode. The username is "administrator". If you did not edit the config file, the password is blank. (In the future, the Evlan VM may allow you to connect as other users, but as of this writing such functionality is not implemented. Note that Evlan users have nothing to do with your OS's users.)

Once connected, you can enter Evlan expressions to have them evaluated, among other things. Try "1 + 1", for example. For a detailed description of the interpreter's built-in directives, type "/help". Additionally, note that pressing ctrl+up/down will allow you to access the command history, and pressing shift+enter will insert a newline rather than execute the command.

The first time you connect, two variables will be defined in the local scope: "system" and "console". "system" is an object representing your capabilities as the administrator. Go ahead and type "/list system" to see what kind of stuff it contains. "console" represents capabilities associated with the current connection. You can use it to, for example, write a message to your command client. The "console" object is tied to your current connection, and is no longer useful after you log out.

You can define new variables in the local scope as explained in the "/help" text. These variables will continue to exist when you close the client. The next time you connect, they will be there. If you save the current VM state, close the VM, run the VM again restoring the state, and connect again, your local variables will still be there.

Note that, as of this writing, there are some things you can do as administrator that could be used by malicious users to harm the system on which the VM is running. So, don't let anyone you don't trust log in as administrator.

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