[SOLVED] How can I pass an argument to a PowerShell script?

How can I pass an argument to a PowerShell script?

There's a PowerShell script named itunesForward.ps1 that makes iTunes fast forward 30 seconds:

$iTunes = New-Object -ComObject iTunes.Application

if ($iTunes.playerstate -eq 1)
{
  $iTunes.PlayerPosition = $iTunes.PlayerPosition + 30
}

It is executed with a prompt line command:

powershell.exe itunesForward.ps1

Is it possible to pass an argument from the command line and have it applied in the script instead of the hardcoded 30 seconds value?

Solution

Tested as working:

#Must be the first statement in your script (not counting comments)
param([Int32]$step=30) 

$iTunes = New-Object -ComObject iTunes.Application

if ($iTunes.playerstate -eq 1)
{
  $iTunes.PlayerPosition = $iTunes.PlayerPosition + $step
}

Call it with

powershell.exe -file itunesForward.ps1 -step 15

Multiple parameters syntax (comments are optional, but allowed):

<#
    Script description.

    Some notes.
#>
param (
    # height of largest column without top bar
    [int]$h = 4000,
    
    # name of the output image
    [string]$image = 'out.png'
)

And some example for advanced parameters, e.g. Mandatory:

<#
    Script description.

    Some notes.
#>
param (
    # height of largest column without top bar
    [Parameter(Mandatory=$true)]
    [int]$h,
    
    # name of the output image
    [string]$image = 'out.png'
)

Write-Host "$image $h"

A default value will not work with a mandatory parameter. You can omit the =$true for advanced parameters of type boolean [Parameter(Mandatory)].