プロセスのコマンドラインを取得する関数

Get-ProcessCommandline.ps1

<#
.SYNOPSIS
    Get the command line of a process.
#>
function Get-ProcessCommandline {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory = $true)]
        [int]$Id
    )
    if ($Id -lt 0) {
        return ""
    }

    # Windows PowerShell
    if ($null -eq $PSEdition -or "Desktop" -eq $PSEdition) {
        $proc = Get-WmiObject -Class Win32_Process -Filter "ProcessId = $Id" -Property "ProcessId", "CommandLine"
        if ($null -eq $proc) {
            return ""
        }
        return $proc.CommandLine
    }
    # PowerShell Core on Windows
    if ($IsWindows) {
        $proc = Get-CimInstance -Class Win32_Process -Filter "ProcessId = $Id" -Property "ProcessId", "CommandLine"
        if ($null -eq $proc) {
            return ""
        }
        return $proc.CommandLine
    }
    # PowerShell Core on macOS
    if ($IsMacOS) {
        return (/bin/ps -o command= -p $Id)
    }
    # PowerShell Core on Linux
    if (-not (Test-Path -LiteralPath "/proc/$Id")) {
        return ""
    }
    return @(Get-Content -LiteralPath "/proc/$Id/cmdline")[0] -replace "\0", " "
}

# 実行例
Get-Process | ForEach-Object {
    [PSCustomObject]@{
        Name        = $_.Name;
        CommandLine = (Get-ProcessCommandline -Id $_.Id);
    }
} | Format-List