# Chapter1: Write a basic powershell script

## The following items will be introduced in the following section:

* 1.Parameters

## 1.Parameters

* powershell用param來定義參數
  * 例如

    ```
      param (
          [string]$price = 100, 
          [string]$ComputerName = $env:computername,    
          [string]$username = $(throw "-username is required."),
          [string]$password = $( Read-Host -asSecureString "Input password" )
          [switch]$SaveData = $false
      )
      write-output "First argument is $price"
      write-output "Second argument is $ComputerName"
      write-output "The True/False switch argument is $SaveData"
    ```
  * 呼叫方法可為:

    ```
     .\demo.ps1 -ComputerName "\\server64" -SaveData
    ```

    * or setting -SaveData to $FALSE:

      ```
       .\demo.ps1 -ComputerName "\\server64" -SaveData:$false
      ```
* Parameter Attributes
  * 例如

    ```
      [Parameter(Mandatory = $true)] 
    ```

    * Mandatory
      * 參數是否必備: $true-設為必備/ $false-設為option