是一个特殊的变量,在Powershell脚本中用于检查前一个命令是否执行成功。它的值为布尔类型,如果前一个命令执行成功,则$?的值为$True,否则为$False。 在do until循环中,可以使用$?来判断循环是否需要继续执行。do until循环是一种先执行循环体中的代码,然后判断条件是否为真的循环结构。当循环体执行完毕后,Power...
Do..Until 构造运行脚本块,直到指定条件为 true。 此构造保证脚本块至少运行一次。 Do..Until 构造使用以下语法: PowerShell 复制 Do { Write-Host "Script block to process" } Until ($answer -eq "stop") While While 构造运行脚本块,直到指定条件为 false。 虽然它类似于 Do..While 构造,...
如果未发现进程,Get-Process将会抛出一个异常,所以传递-ErrorAction SilentlyContinue参数执行容错处理。如果未发现进程仅仅返回一个$null值,则该值会被转换为$false并退出循环。为了不让CPU总是执行无谓。循环而消耗资源,在每个循环过程中调用了sleep命令,在每次循环过程中执行一秒钟的任务后挂起。 如果条件表达式初始化为...
-is 类型鉴别器 用法: $a = 100 $a -is [int] 返回结果:Ture $a -is [string] 返回结果:False -as 类型转换器 用法: 1 -as [string] #将1作为字符串处理 -band 二进制与 -bor 二进制或 -bnot 二进制非 8.运算符优先级 (){} @$ ! [] . & ++或者-- 一元+ - * / % 二元+ - 比较...
SimpleMatch 参数使用默认值 false。 搜索不区分大小写,因为 CaseSensitive 参数设置为 false。 PowerShell 复制 Select-Str -Path notes -Pattern "over*" -SimpleMatch -CaseSensitive:$false 将显示以下输出。 输出 复制 IgnoreCase : True LineNumber : 45 Line : Override StopProcessing Path : C:...
Like aDo-Whileloop, aDo-Untilloop always runs at least once before the condition is evaluated. However, the script block runs only while the condition is false. Thecontinueandbreakflow control keywords can be used in aDo-Whileloop or in aDo-Untilloop. ...
The loop is repeated until the condition becomes $false. The Repeat placeholder represents one or more commands, separated by commas, that are executed each time the loop repeats. Typically, this is used to modify a variable that is tested inside the Condition part of the statement. The ...
if ($result -ge 0) { write-host "Found '222' in ListBox!" } else { write-host "Did NOT find '222' in ListBox" $pass = $false } A slightly unusual quirk of Windows PowerShell is its use of Boolean comparison operators, such as -ge ("greater than or equal to") and -eq ...
if ($result -ge 0) { write-host "Found '222' in ListBox!" } else { write-host "Did NOT find '222' in ListBox" $pass = $false } A slightly unusual quirk of Windows PowerShell is its use of Boolean comparison operators, such as -ge ("greater than or equal to") and -eq (...
totrue. Awhileloop checks for this before running your script block, whereas ado..whileloop checks the condition after running your script block. Ado..untilloop is exactly like ado..whileloop, except that it exits when its condition returns$true, rather than when its condition returns$false....