Update README.md

README.md

@@ -4,8 +4,7 @@ node-config-ts
 [![Greenkeeper badge](https://badges.greenkeeper.io/tusharmath/node-config-ts.svg)](https://greenkeeper.io/)
 
 A simple node configuration manager for typescript based projects. 
-It automatically generates typings for the project based on the default configuration.
-
+**It automatically generates typings**
 
 ## Usage
 
@@ -28,7 +27,7 @@ It automatically generates typings for the project based on the default configur
     root/
     └── config/
         └── default.json
-    ```     
+    ```
     `default.json` should contain your application's configuration
 
 4. Create typings
@@ -38,6 +37,7 @@ It automatically generates typings for the project based on the default configur
     A new `Config.d.ts` will be generated automatically. This file could be ignored from git as it gets automatically generated based on the structure of `default.json`
 
 5. Import and use `node-config-ts`
+
     ```typescript
     import {config} from 'node-config-ts'
    
@@ -46,22 +46,23 @@ It automatically generates typings for the project based on the default configur
 
 ## Directory Structure
 Configurations are loaded via config files that are written in JSON format for now. A typical project looks like this —
-    ```
-    root/
-    └── config/
-        ├── Config.d.ts
-        ├── default.json
-        ├── deployment/
-        │   ├── staging.example.com.json
-        │   ├── production.example.com.json
-        │   └── qa.example.com.json
-        ├── env/
-        │   └── production.json
-        └── user/
-            ├── ec2-user.json
-            ├── andy.json
-            └── sara.json
-    ```
+
+```
+root/
+└── config/
+    ├── Config.d.ts
+    ├── default.json
+    ├── deployment/
+    │   ├── staging.example.com.json
+    │   ├── production.example.com.json
+    │   └── qa.example.com.json
+    ├── env/
+    │   └── production.json
+    └── user/
+        ├── ec2-user.json
+        ├── andy.json
+        └── sara.json
+```
 
 There are three directories in which a project can have configurations — `deployment`, `env` and `user`. These directories can have multiple files inside them and based on the environment variables an appropriate config file is selected for overriding the base `default.json`. For instance if the `NODE_ENV` variable is set to `production` the `env/production.json` configuration will be merged with `default.json`. Similarly if `DEPLOYMENT` env variable is set to `staging.example.com` then `deployment/staging.example.com.json`  is merged with the other configs. Here is a table for environment to directory mapping —
 
@@ -80,3 +81,17 @@ The configs are merged in the following order of priority —
 2. User
 3. Deployment
 4. Environment
+
+The command line arguments can override  all the configuration params. This is useful when you want to start a node server by passing the port externally  —
+
+```bash
+node server.js --port 3000
+```
+
+In the above case even if the `default.json` has a port setting of `9000` the cli argument can override it
+```json
+// default.json
+{
+    "port": 9000
+}
+```