Implementation flow for vShell extensions

This topic presents a top-level view of how to add a command to your vShell instance.

1. Open a Python editor or integrated development environment (IDE) and create a new *.py file.
2. Type the required from vsh import statement.
   

   # Import Python functions from the vsh module
   from vsh import output, cmdparser

3. Create the target function.
   

   # Define the function that the command will call.
   def hello(username):
   
       output("Hello %s, how are you doing?", username)

4. Create the command that calls the target function.
   

   # cmdparser(<target-function>, <syntax>, <msg>)
   cmdparser(hello, "hello:%s", "Say hello to someone")

5. Save the file and copy it to the ~/.vsh directory.
   

   bash$ cp demo.py ~/.vsh

6. Start vShell.
   

   $ vsh
   For help anytime, type '?'
   When you're done, type '^D'
   (vsh)

7. Verify that the command you created is available.
   

   (vsh) ?
    clear                   Clear
    connect                 Connect console
    create                  Provisioning
    hello                   Say hello to someone
    delete                  Destroy
    exit                    Exit shell
    help                    Get help
    list                    Show running devices
    poweroff                Power off device
    poweron                 Power on device
    show                    Show info
    start                   Power on and connect 
    system                  Bridge daemon control

8. Enter the command—with required parameters—and verify that it performs as expected.
   

   (vsh) hello Mark
    Hello Mark, how are you doing?

   

   Note

   The command you created will load every time you log in to this instance of vShell.