diff --git a/shelljs/shelljs-tests.ts b/shelljs/shelljs-tests.ts
index d28b72398..835f177a6 100644
--- a/shelljs/shelljs-tests.ts
+++ b/shelljs/shelljs-tests.ts
@@ -85,8 +85,34 @@ shell.ln("-sf", "file", "existing");
 
 var testPath = shell.env["path"];
 
+import child = require("child_process");
+
 var version = shell.exec("node --version").output;
 
+var version2 = <shell.ExecOutputReturnValue>shell.exec("node --version", { async: false });
+var output = version2.output;
+
+var asyncVersion3 = <child.ChildProcess>shell.exec("node --version", { async: true });
+var pid = asyncVersion3.pid;
+
+shell.exec("node --version", { silent: true }, function (code, output) {
+    var version = output;
+});
+shell.exec("node --version", { silent: true, async: true }, function (code, output) {
+    var version = output;
+});
+shell.exec("node --version", function (code, output) {
+    var version = output;
+});
+shell.exec("node --version", function (code: number) {
+    var num: number = code;
+});
+
+var childProc = shell.exec("node --version", function (code: number) {
+    var num: number = code;
+});
+var pid = childProc.pid;
+
 shell.chmod(755, "/Users/brandon");
 shell.chmod("755", "/Users/brandon"); // same as above
 shell.chmod("u+x", "/Users/brandon");
diff --git a/shelljs/shelljs.d.ts b/shelljs/shelljs.d.ts
index b3b732d05..c4608caee 100644
--- a/shelljs/shelljs.d.ts
+++ b/shelljs/shelljs.d.ts
@@ -8,6 +8,8 @@
 
 declare module "shelljs"
 {
+    import child = require("child_process");
+
     /**
      * Changes to directory dir for the duration of the script
      * @param {string} dir Directory to change in.
@@ -434,31 +436,44 @@ declare module "shelljs"
      * Object containing environment variables (both getter and setter). Shortcut to process.env.
      */
     export var env: { [key: string]: string };
-
-    /*
-
-    // Not yet implemented due to implementation issues (constant overloads and return types).
-    // See: https://github.com/arturadib/shelljs#execcommand--options--callback
-
-    export function exec(command: string, options: ExecOptions, callback: (code: number, output: string) => any): any;
-    export function exec(command: string, options: ExecOptions): any;
-
-    interface ExecOptions
-    {
-        silent: boolean;
-        async: boolean;
-    }
-
-    */
-
+    
     /**
      * Executes the given command synchronously.
-     * @param  {string}          command The commadn to execute.
-     * @return {ExecReturnValue}         Returns an object containing the return code and output as string.
+     * @param  {string}                 command The command to execute.
+     * @return {ExecOutputReturnValue}          Returns an object containing the return code and output as string.
      */
-    export function exec(command: string): ExecReturnValue;
+    export function exec(command: string): ExecOutputReturnValue;
+    /**
+     * Executes the given command synchronously.
+     * @param  {string}                                     command The command to execute.
+     * @param  {ExecOptions}                                options Silence and synchronous options.
+     * @return {ExecOutputReturnValue | child.ChildProcess}         Returns an object containing the return code and output as string, or if {async:true} was passed, a ChildProcess.
+     */
+    export function exec(command: string, options: ExecOptions): ExecOutputReturnValue | child.ChildProcess;
+    /**
+     * Executes the given command synchronously.
+     * @param  {string}          command  The command to execute.
+     * @param  {ExecOptions}     options  Silence and synchronous options.
+     * @param  {ExecCallback}    callback Receives code and output asynchronously.
+     */
+    export function exec(command: string, options: ExecOptions, callback: ExecCallback): child.ChildProcess;
+    /**
+     * Executes the given command synchronously.
+     * @param  {string}          command  The command to execute.
+     * @param  {ExecCallback}    callback Receives code and output asynchronously.
+     */
+    export function exec(command: string, callback: ExecCallback): child.ChildProcess;
 
-    interface ExecReturnValue
+    export interface ExecCallback {
+        (code: number, output: string): any;
+    }
+
+    export interface ExecOptions {
+        silent?: boolean;
+        async?: boolean;
+    }
+
+    export interface ExecOutputReturnValue
     {
         code: number;
         output: string;