Add CommandLine property to Process (#12288)

src/System.Management.Automation/engine/TypeTable_Types_Ps1Xml.cs

@@ -1139,6 +1139,24 @@ namespace System.Management.Automation.Runspaces
                 typeMembers,
                 isOverride: false);
 
+            newMembers.Add(@"CommandLine");
+            AddMember(
+                errors,
+                typeName,
+                new PSScriptProperty(
+                    @"CommandLine",
+                    GetScriptBlock(@"
+                        if ($IsWindows) {
+                            (Get-CimInstance Win32_Process -Filter ""ProcessId = $($this.Id)"").CommandLine
+                        } elseif ($IsLinux) {
+                            Get-Content -LiteralPath ""/proc/$($this.Id)/cmdline""
+                        }
+                    "),
+                    setterScript: null,
+                    shouldCloneOnAccess: true),
+                typeMembers,
+                isOverride: false);
+
             newMembers.Add(@"Parent");
             AddMember(
                 errors,

test/powershell/Modules/Microsoft.PowerShell.Management/Get-Process.Tests.ps1

@@ -89,6 +89,12 @@ Describe "Get-Process" -Tags "CI" {
     It "Should fail to run Get-Process with -FileVersionInfo without admin" -Skip:(!$IsWindows) {
         { Get-Process -FileVersionInfo -ErrorAction Stop } | Should -Throw -ErrorId "CouldNotEnumerateFileVer,Microsoft.PowerShell.Commands.GetProcessCommand"
     }
+
+    It "Should return CommandLine property" -Skip:($IsMacOS)  {
+        $command = "(Get-Process -Id `$pid).CommandLine"
+        $result = & "$PSHOME/pwsh" -NoProfile -NonInteractive -Command $command
+        $result | Should -BeLike "*$command*"
+    }
 }
 
 Describe "Get-Process Formatting" -Tags "Feature" {