Using a variable in a PowerShell script

Question

I'm trying to put a small collection of simple scripts together for PowerShell to make life easier but am having some problems with variables in these scripts.

In a Linux environment I would use a variable in my scripts (usually $1, $2, etc....) like this to make things easier

sed -i 's/$1/$2/g' filename.conf

So that all I would need to do is this

./findreplace.sh old new filename.conf

In powershell, I want to achieve similar, specifically with this command:

Get-ADPrincipalGroupMembership account.name | select name

In this case, the $1 would be where 'user.name' is, so that I would be doing:

 .\groups.ps1 user.name

Is there the facility for this?

Answer 1

Groups.ps1 should have the following content:

param( $user )

Get-ADPrincipalGroupMembership $user | Select Name

You can then invoke it as shown, or as .\Groups.ps1 -user user.name.

However, I'd probably try to do it as an "advanced command", and allow it to handle multiple names, and also names passed in via the pipeline:

[CmdletBinding()]

param (
    [Parameter(ValueFromPipeline=$true;ValueFromPipelineByPropertyName=$true)]
    [Alias("Identity","sAMAccountName")
    string[] $Users
)

PROCESS {
    ForEach ($User in $Users) {
        Get-ADPrincipalGroupMembership $User | Select Name
    }
}

which would also allow you to do something like Get-ADUser | .\Groups.ps1

Answer 2

You can add for loop form example script above:

for ($i = 0; $i -lt $args.Length; $i++) { Set-Variable -Scope Script -Name ($i + 1) -Value $args[$i] }

Write-Host "1: $1"
Write-Host "2: $2"

But more easy is just to declare script parameter as:

param($1, $2)

Write-Host "1: $1"
Write-Host "2: $2"

By the way it's bad practice to declare variables as numbers.