Access to elements of $_

Question

In order to create symlinks in PowerShell, you need to use the following command :

New-Item -Path C:	emp\myLink -Target C:\Users\{me}\Documents	arget.txt -ItemType SymbolicLink

I would like to implement a more straightforward syntax as shown below :

"C:	emp\myLink", "C:\Users\{me}\Documents	arget.txt" | Ln

Ln is a filter defined as such :

filter Ln {
     New-Item -Path $_[0] -Target  $_[1] -ItemType SymbolicLink
}

However, it doesn't work, and I would like to know how to access single elements of $_, for instance in our case shouldn't we have $_[0] == "C: emp\myLink" ?

Thanks in advance for your help !

user_15339544 · Answer

If you want to use the syntax proposed in your question an easy workaround would be to change your filter for a non-advanced function and utilize the automatic variable $input to collect both paths being passed through the pipeline:

function Ln {
    $params = @($input)
    if($params.Count -ne 2) {
        throw 'Unsoported!'
    }
    New-Item -Path $params[0] -Target $params[1] -ItemType SymbolicLink
}

"C:	emp\myLink", "C:\Users\{me}\Documents	arget.txt" | Ln

user_4085331 · Answer

When you pipe values like this they are fed one at a time. You can test this with a little "debug" version of your filter

filter Ln {
     write-host $_[0] -ForeGroundColor Cyan
     Write-Host $_[1] -ForeGroundColor Green
}

You will see it's a single string that we are grabbing the first and second character from

If you want to send both elements together

https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_operators?view=powershell-7.2#comma-operator-

Access to elements of $_

2 Answers