PowerShell · PaulHigin · Mar 27, 2023 · Mar 20, 2023 · Mar 20, 2023 · Mar 20, 2023
diff --git a/src/Microsoft.PowerShell.Commands.Management/commands/management/Process.cs b/src/Microsoft.PowerShell.Commands.Management/commands/management/Process.cs
@@ -1823,6 +1823,26 @@ public SwitchParameter UseNewEnvironment
 
         private SwitchParameter _UseNewEnvironment;
 
+        /// <summary>
+        /// Gets or sets the environment variables for the process.
+        /// </summary>
+        [Parameter]
+        public Hashtable Environment
+        {
+            get
+            {
+                return _environment;
+            }
+
+            set
+            {
+                _environment = value;
+                _isDefaultSetParameterSpecified = true;
+            }
+        }
+
+        private Hashtable _environment;
+
         #endregion
 
         #region overrides
@@ -1929,8 +1949,13 @@ protected override void BeginProcessing()
                 if (_UseNewEnvironment)
                 {
                     startInfo.EnvironmentVariables.Clear();
-                    LoadEnvironmentVariable(startInfo, Environment.GetEnvironmentVariables(EnvironmentVariableTarget.Machine));
-                    LoadEnvironmentVariable(startInfo, Environment.GetEnvironmentVariables(EnvironmentVariableTarget.User));
+                    LoadEnvironmentVariable(startInfo, System.Environment.GetEnvironmentVariables(EnvironmentVariableTarget.Machine));
+                    LoadEnvironmentVariable(startInfo, System.Environment.GetEnvironmentVariables(EnvironmentVariableTarget.User));
+                }
+
+                if (_environment != null)
+                {
+                    LoadEnvironmentVariable(startInfo, _environment);
                 }
 
                 startInfo.WindowStyle = _windowstyle;
@@ -2176,13 +2201,20 @@ private static void LoadEnvironmentVariable(ProcessStartInfo startinfo, IDiction
                     processEnvironment.Remove(entry.Key.ToString());
                 }
 
-                if (entry.Key.ToString().Equals("PATH"))
+                if (entry.Value != null)
                 {
-                    processEnvironment.Add(entry.Key.ToString(), Environment.GetEnvironmentVariable(entry.Key.ToString(), EnvironmentVariableTarget.Machine) + ";" + Environment.GetEnvironmentVariable(entry.Key.ToString(), EnvironmentVariableTarget.User));
-                }
-                else
-                {
-                    processEnvironment.Add(entry.Key.ToString(), entry.Value.ToString());
+                    if (entry.Key.ToString().Equals("PATH"))
+                    {
+#if UNIX
+                        processEnvironment.Add(entry.Key.ToString(), entry.Value.ToString());
+#else
+                        processEnvironment.Add(entry.Key.ToString(), entry.Value.ToString() + Path.PathSeparator + System.Environment.GetEnvironmentVariable(entry.Key.ToString(), EnvironmentVariableTarget.Machine) + Path.PathSeparator + System.Environment.GetEnvironmentVariable(entry.Key.ToString(), EnvironmentVariableTarget.User));
+#endif
+                    }
+                    else
+                    {
+                        processEnvironment.Add(entry.Key.ToString(), entry.Value.ToString());
+                    }
                 }
             }
         }

diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Start-Process.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Start-Process.Tests.ps1
@@ -181,7 +181,7 @@ Describe "Start-Process tests requiring admin" -Tags "Feature","RequireAdminOnWi
     }
 }
 
-Describe "Start-Process" -Tags "Feature" {
+Describe "Environment Tests" -Tags "Feature" {
 
     It "UseNewEnvironment parameter should reset environment variables for child process" {
 
@@ -206,4 +206,33 @@ Describe "Start-Process" -Tags "Feature" {
             $env:TestEnvVariable = $null
         }
     }
+
+    It '-Environment adds or replaces environment variables to child process' {
+        $outputfile = Join-Path -Path $TestDrive -ChildPath output.txt
+        Start-Process pwsh -ArgumentList '-NoProfile','-Nologo','-OutputFormat xml','-Command get-childitem env:' -Wait -Environment @{ a = 1; B = 'hello'; TERM = 'dumb'; PATH = 'mine' } -RedirectStandardOutput $outputfile
+        $out = Import-Clixml $outputfile
+        ($out | Where-Object { $_.Name -eq 'a' }).Value | Should -Be 1
+        ($out | Where-Object { $_.Name -eq 'B' }).Value | Should -BeExactly 'hello'
+        ($out | Where-Object { $_.Name -eq 'TERM' }).Value | Should -BeExactly 'dumb'
+        $pathSeparator = [System.IO.Path]::PathSeparator
+        if ($IsWindows) {
+            ($out | Where-Object { $_.Name -eq 'PATH' }).Value | Should -BeLike "*${pathSeparator}mine${pathSeparator}*"
+        } else {
+            ($out | Where-Object { $_.Name -eq 'PATH' }).Value | Should -BeLike "*${pathSeparator}mine"
+        }
+    }
+
+    It '-Environment can remove an environment variable from child process' {
+        try {
+            $env:existing = 1 # set a variable that we will remove
+            $env:nonexisting = $null # validate that removing a non-existing variable is a no-op
+            $outputfile = Join-Path -Path $TestDrive -ChildPath output.txt
+            Start-Process pwsh -ArgumentList '-NoProfile','-Nologo','-OutputFormat xml','-Command get-childitem env:' -Wait -Environment @{ existing = $null; nonexisting = $null } -RedirectStandardOutput $outputfile
+            $out = Import-Clixml $outputfile
+            $out | Where-Object { $_.Name -eq 'existing' } | Should -BeNullOrEmpty
+            $out | Where-Object { $_.Name -eq 'nonexisting' } | Should -BeNullOrEmpty
+        } finally {
+            $env:existing = $null
+        }
+    }
 }