diff --git a/src/vs/code/electron-main/env.ts b/src/vs/code/electron-main/env.ts
index e729e48bc5b..91e7ce50d84 100644
--- a/src/vs/code/electron-main/env.ts
+++ b/src/vs/code/electron-main/env.ts
@@ -142,11 +142,6 @@ export class EnvService implements IEnvService {
 		}
 
 		const argv = parseArgs(args);
-
-		const debugBrkExtensionHostPort = getNumericValue(argv.debugBrkPluginHost, 5870);
-		const debugExtensionHostPort = getNumericValue(argv.debugPluginHost, 5870, this.isBuilt ? void 0 : 5870);
-		const debugPluginHost = debugBrkExtensionHostPort ? String(debugBrkExtensionHostPort) : debugExtensionHostPort ? String(debugExtensionHostPort): void 0;
-		const debugBrkPluginHost = debugBrkExtensionHostPort ? String(true) : void 0;
 		const paths = parsePathArguments(this._currentWorkingDirectory, argv._, argv.goto);
 		const timestamp = parseInt(argv.timestamp);
 		const debugBrkFileWatcherPort = getNumericValue(argv.debugBrkFileWatcherPort, void 0);
@@ -157,8 +152,8 @@ export class EnvService implements IEnvService {
 			timestamp: types.isNumber(timestamp) ? String(timestamp) : '0',
 			performance: argv.performance,
 			verbose: argv.verbose,
-			debugPluginHost,
-			debugBrkPluginHost,
+			debugPluginHost: argv.debugPluginHost,
+			debugBrkPluginHost: argv.debugBrkPluginHost,
 			logExtensionHostCommunication: argv.logExtensionHostCommunication,
 			debugBrkFileWatcherPort: debugBrkFileWatcherPort ? String(debugBrkFileWatcherPort) : void 0,
 			'new-window': argv['new-window'],
@@ -293,14 +288,6 @@ function normalizePath(p?: string): string {
 	return p ? path.normalize(p) : p;
 }
 
-export function getPlatformIdentifier(): string {
-	if (process.platform === 'linux') {
-		return `linux-${process.arch}`;
-	}
-
-	return process.platform;
-}
-
 export interface IParsedPath {
 	path: string;
 	line?: number;
@@ -332,7 +319,7 @@ export function parseLineAndColumnAware(rawPath: string): IParsedPath {
 	};
 }
 
-export function toLineAndColumnPath(parsedPath: IParsedPath): string {
+function toLineAndColumnPath(parsedPath: IParsedPath): string {
 	let segments = [parsedPath.path];
 
 	if (types.isNumber(parsedPath.line)) {
diff --git a/src/vs/code/node/argv.ts b/src/vs/code/node/argv.ts
index 20e756c1380..a8f2274bbf0 100644
--- a/src/vs/code/node/argv.ts
+++ b/src/vs/code/node/argv.ts
@@ -42,7 +42,9 @@ const options: minimist.Opts = {
 		'extensionTestsPath',
 		'timestamp',
 		'install-extension',
-		'uninstall-extension'
+		'uninstall-extension',
+		'debugBrkPluginHost',
+		'debugPluginHost'
 	],
 	boolean: [
 		'help',
diff --git a/src/vs/platform/environment/node/environmentService.ts b/src/vs/platform/environment/node/environmentService.ts
index 21f61ced9b3..062d00123b5 100644
--- a/src/vs/platform/environment/node/environmentService.ts
+++ b/src/vs/platform/environment/node/environmentService.ts
@@ -78,12 +78,17 @@ export class EnvironmentService implements IEnvironmentService {
 
 		this._extensionDevelopmentPath = args.extensionDevelopmentPath;
 
-		if (args.debugPluginHost) {
-			this._debugExtensionHostPort = Number(args.debugPluginHost);
-		}
-
-		this._debugBrkExtensionHost = Boolean(args.debugBrkPluginHost);
+		const { port, brk } = parseExtensionHostPort(args, this.isBuilt);
+		this._debugExtensionHostPort = port;
+		this._debugBrkExtensionHost = brk;
 
 		this._debugBrkFileWatcherPort = (typeof args.debugBrkFileWatcherPort === 'string') ? Number(args.debugBrkFileWatcherPort) : void 0;
 	}
+}
+
+export function parseExtensionHostPort(args: ParsedArgs, isBuild: boolean): { port: number; brk: boolean; } {
+	const portStr = args.debugBrkPluginHost || args.debugPluginHost;
+	const port = Number(portStr) || (!isBuild ? 5870 : null);
+	const brk = port ? Boolean(!!args.debugBrkPluginHost) : false;
+	return { port, brk };
 }
\ No newline at end of file
diff --git a/src/vs/platform/environment/test/node/environmentService.test.ts b/src/vs/platform/environment/test/node/environmentService.test.ts
new file mode 100644
index 00000000000..8e8db20a8ec
--- /dev/null
+++ b/src/vs/platform/environment/test/node/environmentService.test.ts
@@ -0,0 +1,34 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import * as assert from 'assert';
+import { parseArgs } from 'vs/code/node/argv';
+import { parseExtensionHostPort } from 'vs/platform/environment/node/environmentService';
+
+suite('EnvironmentService', () => {
+
+	test('parseExtensionHostPort when built', () => {
+		const parse = a => parseExtensionHostPort(parseArgs(a), true);
+
+		assert.deepEqual(parse([]), { port: null, brk: false });
+		assert.deepEqual(parse(['--debugPluginHost']), { port: null, brk: false });
+		assert.deepEqual(parse(['--debugPluginHost=1234']), { port: 1234, brk: false });
+		assert.deepEqual(parse(['--debugBrkPluginHost']), { port: null, brk: false });
+		assert.deepEqual(parse(['--debugBrkPluginHost=5678']), { port: 5678, brk: true });
+		assert.deepEqual(parse(['--debugPluginHost=1234', '--debugBrkPluginHost=5678']), { port: 5678, brk: true });
+	});
+
+	test('parseExtensionHostPort when unbuilt', () => {
+		const parse = a => parseExtensionHostPort(parseArgs(a), false);
+
+		assert.deepEqual(parse([]), { port: 5870, brk: false });
+		assert.deepEqual(parse(['--debugPluginHost']), { port: 5870, brk: false });
+		assert.deepEqual(parse(['--debugPluginHost=1234']), { port: 1234, brk: false });
+		assert.deepEqual(parse(['--debugBrkPluginHost']), { port: 5870, brk: false });
+		assert.deepEqual(parse(['--debugBrkPluginHost=5678']), { port: 5678, brk: true });
+		assert.deepEqual(parse(['--debugPluginHost=1234', '--debugBrkPluginHost=5678']), { port: 5678, brk: true });
+	});
+});
\ No newline at end of file