What does mean in PowerShell

Question

I ve seen the following a lot in PowerShell  but what does it do exactly

User · Answer

According to this website  it s a reference to this  mostly in loops          dollar underscore     THIS  token  Typically refers to the   item inside a foreach loop     Task    Print all items in a collection    Solution        foreach   Write-Host

User · Answer

This is the variable for the current value in the pipe line  which is called  PSItem in Powershell 3 and newer     1 2 3      write-host         or  1 2 3      write-host  PSItem      For example in the above code the     block is called for every value in the array   The    or  PSItem variable will contain the current value

User · Answer

I think the easiest way to think about this variable like input parameter in lambda expression in C   I e     is similar to x in x   gt  Console WriteLine x  anonymous function in C   Consider following examples   PowerShell   1 2 3   ForEach-Object  Write-Host       Prints   1 2 3   or  1 2 3   Where-Object     -gt 1    Prints   2 3   And compare this with C  syntax using LINQ   var list   new List lt int gt    1  2  3    list ForEach      gt  Console WriteLine          Prints   1 2 3   or  list Where      gt     gt  1       ToList        ForEach s   gt  Console WriteLine s      Prints   2 3

User · Answer

is an variable which iterates over each object element passed from the previous    pipe

User · Answer

is an alias for automatic variable  PSItem  introduced in PowerShell V3 0  Usage information found here  which represents the current item from the pipe   PowerShell  v6 0  online documentation for automatic variables is here

User · Answer

is a variable created by the system usually inside block expressions that are referenced by cmdlets that are used with pipe such as Where-Object and ForEach-Object    But it can be used also in other types of expressions  for example with Select-Object combined with expression properties  Get-ChildItem   Select-Object   Name  Name  Expression     Name    In this case the    represents the item being piped but multiple expressions can exist   It can also be referenced by custom parameter validation  where a script block is used to validate a value  In this case the    represents the parameter value as received from the invocation   The closest analogy to c  and java is the lamda expression  If you break down powershell to basics then everything is a script block including a script file a  functions and cmdlets  You can define your own parameters but in some occasions one is created by the system for you that represents the input item to process evaluate  In those situations the automatic variable is

[powershell] What does $_ mean in PowerShell?

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