以下示例检查$string变量在PowerShell中是否为NULL。如果变量不为NULL或空,则返回第一个语句,如果变量为NULL或空,则返回第二个语句。 if($string){Write-Host"The variable is not null."}else{Write-Host"The variable is null."} 输出: The variable is not null. 让我们为变量分配一个空字符串值并再次检...
ComputerName Verbose Debug ErrorAction WarningAction InformationAction ErrorVariable WarningVariable InformationVariable OutVariable OutBuffer PipelineVariable WhatIf Confirm 参数验证 尽早验证输入。 如果没有有效输入则无法完成,不允许代码继续执行。 参数变量必须始终指定数据类型。 在下面的示例中,String被指定为Comput...
if ( (Get-Process) -and (Get-Service) ) 檢查$null在語句中沒有結果或 $null 值評估為 $false if。 特別 $null檢查 時,最佳做法是將 放在 $null 左側。PowerShell 複製 if ( $null -eq $value ) 處理PowerShell 中的值時 $null ,有相當多的細微差別。 如果你有興趣深入潛水,我有一篇文章,關於...
Check the spelling of the name, or if a path was included, verify that the path is correct and try again. 因為PowerShell 無法辨識 nonsenseString 為Cmdlet 或其他專案,所以會傳回 CommandNotFoundException 錯誤。 特定 trap 語句會設陷這個終止錯誤。 下列文稿範例包含具有相同錯誤的語句 trap: Power...
$i = 0 foreach ($num in ("one","two","three")) { "Iteration: $i" $i++ "`tNum: $num" "`tCurrent: $($foreach.Current)" if ($foreach.Current -eq "two") { "Before MoveNext (Current): $($foreach.Current)" $foreach.MoveNext() | Out-Null "After MoveNext (Current): $...
In PowerShell, checking if a variable is null (or in PowerShell terms, $null) is a fundamental task in scripting, especially when dealing with the output of
如果表達式為 false,則會<if-false><condition>執行表達式 例如: PowerShell 複製 $message = (Test-Path $path) ? "Path exists" : "Path not found" 在此範例中,的 值為 $messagePath exists 傳回$true時Test-Path。 傳回 $false時Test-Path,的值$message是Path not found。 PowerShell 複製 $se...
function Get-FunctionPosition { [CmdletBinding()] [OutputType('FunctionPosition')] param( [Parameter(Position = 0, Mandatory, ValueFromPipeline, ValueFromPipelineByPropertyName)] [ValidateNotNullOrEmpty()] [Alias('PSPath')] [System.String[]] $Path ) process { try { $filesToProcess = if (...
if(-not (Test-Path $basePath)) { $null = New-Item $basePath -Force } Set-ItemProperty $basePath -Name EnableScriptBlockLogging -Value “1” }function Disable-PSScriptBlockLogging { Remove-Item HKLM:\Software\Policies\Microsoft\Windows\PowerShell\ScriptBlockLogging -Force -Recurse }...
Whether or not the result is an array depends on the number of results that were returned. If more than one, PowerShell returns an array. Otherwise, it returns the result directly so the same command can behave differently from case to case, depending on the number of results. ...