Find modules/commands used by script

Get-Commands.ps1

param($file)

$tokens = $null
$err = $null

$file = Resolve-Path $file
$ast = [System.Management.Automation.Language.Parser]::ParseFile($file, [ref]$tokens, [ref]$err)
$commands = $ast.FindAll({$true},$true) | ? { $_ -is [System.Management.Automation.Language.CommandAst] } | % { $_.CommandElements[0].Value } | Sort-Object -Unique
$sources = [System.Collections.Generic.List[string]]::new()
$commands | % {
    $c = Get-Command $_ -ErrorAction Ignore
    if ($null -eq $c) {
        Write-Error "$_ not found"
    }
    else {
        $null = $sources.Add($c.Source)
    }
}

$sources | Sort-Object -Unique