How to write a cmdlet

This article shows how to write a cmdlet. The Send-Greeting cmdlet takes a single user name as input and then writes a greeting to that user. Although the cmdlet does not do much work, this example demonstrates the major sections of a cmdlet.

Steps to write a cmdlet

1. To declare the class as a cmdlet, use the Cmdlet attribute. The Cmdlet attribute specifies the verb and the noun for the cmdlet name.

   For more information about the Cmdlet attribute, see CmdletAttribute Declaration.

2. Specify the name of the class.

3. Specify that the cmdlet derives from either of the following classes:

   • System.Management.Automation.Cmdlet
   • System.Management.Automation.PSCmdlet

4. To define the parameters for the cmdlet, use the Parameter attribute. In this case, only one required parameter is specified.

   For more information about the Parameter attribute, see ParameterAttribute Declaration.

5. Override the input processing method that processes the input. In this case, the System.Management.Automation.Cmdlet.ProcessRecord method is overridden.

6. To write the greeting, use the method System.Management.Automation.Cmdlet.WriteObject. The greeting is displayed in the following format:

   Hello <UserName>!
   

Example

using System.Management.Automation;  // Windows PowerShell assembly.

namespace SendGreeting
{
  // Declare the class as a cmdlet and specify the
  // appropriate verb and noun for the cmdlet name.
  [Cmdlet(VerbsCommunications.Send, "Greeting")]
  public class SendGreetingCommand : Cmdlet
  {
    // Declare the parameters for the cmdlet.
    [Parameter(Mandatory=true)]
    public string Name
    {
      get { return name; }
      set { name = value; }
    }
    private string name;

    // Override the ProcessRecord method to process
    // the supplied user name and write out a
    // greeting to the user by calling the WriteObject
    // method.
    protected override void ProcessRecord()
    {
      WriteObject("Hello " + name + "!");
    }
  }
}

See also

System.Management.Automation.Cmdlet

System.Management.Automation.PSCmdlet

System.Management.Automation.Cmdlet.ProcessRecord

System.Management.Automation.Cmdlet.WriteObject

CmdletAttribute Declaration

ParameterAttribute Declaration

Writing a Windows PowerShell Cmdlet