Update README.md

README.md

@@ -80,11 +80,16 @@ The configuration file specifies which rules are enabled and their options. Thes
    *   - a relative path to a JSON file
    */
   "extends": "tslint:latest",
+  "defaultSeverity": "warning",
   "rules": {
     /*
      * Any rules specified here will override those from the base config we are extending.
      */
-    "curly": true
+    "curly": true,
+    "max-line-length": {
+      "severity": "error",
+      "options": 140
+    }
   },
   "jsRules": {
     /*
@@ -109,6 +114,12 @@ __`tslint:latest`__ extends `tslint:recommended` and is continuously updated to
 
 See the [core rules list](#core-rules) below for descriptions of all the rules.
 
+##### Severity
+
+The severity level of each rule can use the values `default`, `error`, `warning`/`warn`, and `off`/`none`. If no severity level is specified, `default` is used. The `defaultSeverity` option replaces the severity level for each rule that uses severity level `default` in the current file. Valid values for `defaultSeverity` include `error`, `warning`/`warn`, and `off`/`none`.
+
+The CLI exits with code 2 if an error is reported, and exits with code 0 otherwise.
+
 #### CLI
 
 usage: `tslint [options] file ...`