Powershell錯誤/異常處理

Question

我在處理有關invoke-command的錯誤/異常時遇到了一些問題。

我試圖捕捉目標計算機不存在的錯誤，但是我顯示的消息和catch塊中腳本的行爲方式讓我覺得有一些我錯過了或錯過理解。

這是有問題的腳本的一部分：

$session = New-Pssession -computername $computerName 
Invoke-Command -session $session -ScriptBlock $command -ArgumentList $sqlServerName, $userToGivePermisions   
Remove-PSsession -session $session 

基本上我想處理錯誤時$computerName不在網絡上有效的計算機。我故意給它一個錯誤的名稱來測試它，我得到以下錯誤：

[dcd] Connecting to remote server failed with the following error message : WinRM cannot process the request. The following error occured while using Kerberos authentication: The network path was not found. 
Possible causes are: 
-The user name or password specified are invalid. 
-Kerberos is used when no authentication method and no user name are specified. 
-Kerberos accepts domain user names, but not local user names. 
-The Service Principal Name (SPN) for the remote computer name and port does not exist. 
-The client and remote computers are in different domains and there is no trust between  the two domains. 
After checking for the above issues, try the following: 
-Check the Event Viewer for events related to authentication. 
-Change the authentication method; add the destination computer to the WinRM TrustedHosts configuration setting or use HTTPS transport. 
Note that computers in the TrustedHosts list might not be authenticated. 
-For more information about WinRM configuration, run the following command: winrm help config. For more information, see the about_Remote_Troubleshooting Help topic. 
+ CategoryInfo   : OpenError: (System.Manageme....RemoteRunspace:RemoteRunspace) [], PSRemotingTransportException 
+ FullyQualifiedErrorId : PSSessionOpenFailed 

[dcd]是不存在的機器的名稱。我將代碼放入try catch中，並使用-contains對錯誤消息進行了檢查。條件總是出錯，我在上面的錯誤中幾乎嘗試過單個單詞。

當我使用$_.exception.message在catch塊中顯示錯誤消息時，我得到了有關$ session爲空的不同錯誤。

當我做了一個-contains使用顯示的錯誤信息中關於$ session的單詞，它仍然返回false我測試的每個單詞。

我不明白其中哪些是錯誤，爲什麼不是-contains永遠返回true。我將-ea stop添加到所有3行以捕獲所有非終止錯誤，但無濟於事。

任何人有任何想法是怎麼回事？

Answer 1

-contains檢查元素是否在數組中。 e.g：

1,2,3 -contains 2 # Is True 
"a","bc","d" -contains "b" # Is False 

嘗試-match或-like運營商來代替。看看comparison operator documentation。