Passing CLI arguments to a function in PowerShell - powershell

Question

I have a PowerShell script that contains several functions. One of the functions should receive command line arguments. Here's a similar script to what I'm doing:
$mydocs = [Environment]::GetFolderPath("MyDocuments")
function example() {
Param(
[string]$name = "testfolder",
[switch]$foo = $false
)
$newdir = $mydocs + "\" + $name
if (!(Test-Path $newdir)) { mkdir $newdir }
}
example
So when I run this:
.\example.ps1 -name anewfolder -foo
I want the function example to use these arguments.
Because of scoping, my function has no $args. I put Write-Host $args into the function to double check, and it returns nothing. How can I pull the parent args, pass them into params, and get example to run with my arguments? Or should I just remove the function and run this part of my code in the parent scope?

Answer 1

If you want to pass arguments to your script, you need to capture them in a Param() block like your Function has. Alternatively, you can access script args with a scope selector like $script:Args.
Param([String]$Name,[Switch]$Foo)
$mydocs = [Environment]::GetFolderPath("MyDocuments")
function example
{
param(
[string]$name,
[switch]$foo
)
$newdir = Join-Path $mydocs $name
if (!(Test-Path $newdir)) { mkdir $newdir }
}
example -Name $Name -Foo
Now, .\example.ps1 -name anewfolder -foo will be successful.

Answer 2

$args inside the function is a different variable than $args in the global scope of the script. A very simple way of passing arbitrary script arguments to your function is to splat $args:
example #args
Note, however, that this isn't a very clean approach. It'd be better to properly parameterize the script and selectively pass those parameters that are meant to go to the function, as TheIncorrigible1 suggested.
Param(
[string]$name,
[int]$bar,
[switch]$foo
)
function example() {
Param(
[string]$name = "testfolder",
[switch]$foo
)
$newdir = "${mydocs}\${name}"
if (!(Test-Path $newdir)) { mkdir $newdir }
}
$params = #{}
if ($PSBoundParameters.ContainsKey('name')) { $params['name'] = $name }
if ($PSBoundParameters.ContainsKey('foo')) { $params['foo'] = $true }
example #params