Added .help() and .version() methods

README.md

@@ -496,10 +496,14 @@ Format usage output to wrap at `columns` many columns.
 Any command-line argument given that is not demanded, or does not have a
 corresponding description, will be reported as an error.
 
-.help()
--------
+.help([option, [description]])
+------------------------------
+
+Add an option (e.g., `--help`) that displays the usage string and exits the
+process. If present, the `description` parameter customises the description of
+the help option in the usage string.
 
-Return the generated usage string.
+If invoked without parameters, `.help` returns the generated usage string.
 
 Example:
 
@@ -511,6 +515,13 @@ console.log(yargs.help());
 
 Later on, ```argv``` can be retrived with ```yargs.argv```
 
+.version(version, option, [description])
+----------------------------------------
+
+Add an option (e.g., `--version`) that displays the version number (given by the
+`version` parameter) and exits the process. If present, the `description`
+parameter customises the description of the version option in the usage string.
+
 .showHelp(fn=console.error)
 ---------------------------
 

example/help.js

@@ -0,0 +1,27 @@
+var yargs = require('../index');
+
+var argv = yargs
+  .usage('This is my awesome program\n\nUsage: $0 [options]')
+  .help('help').alias('help', 'h')
+  .version('1.0.1', 'version').alias('version', 'V')
+  .options({
+    input: {
+      alias: 'i',
+      description: "<filename> Input file name",
+      requiresArg: true,
+      required: true
+    },
+    output: {
+      alias: 'o',
+      description: "<filename> output file name",
+      requiresArg: true,
+      required: true
+    }
+  })
+  .argv;
+
+console.log('Inspecting options');
+console.dir(argv);
+
+console.log("input:", argv.input);
+console.log("output:", argv.output);

index.js

@@ -226,7 +226,7 @@ function Argv (processArgs, cwd) {
             if (opt.count || opt.type === 'count') {
                 self.count(key);
             }
-            
+
             var desc = opt.describe || opt.description || opt.desc;
             if (desc) {
                 self.describe(key, desc);
@@ -236,10 +236,10 @@ function Argv (processArgs, cwd) {
                 self.requiresArg(key);
             }
         }
-        
+
         return self;
     };
-    
+
     var wrap = null;
     self.wrap = function (cols) {
         wrap = cols;
@@ -257,8 +257,28 @@ function Argv (processArgs, cwd) {
         fn(self.help());
         return self;
     };
-
+
+    var version = null;
+    var versionOpt = null;
+    self.version = function (ver, opt, msg) {
+        version = ver;
+        versionOpt = opt;
+        self.describe(opt, msg || 'Show version number');
+        return self;
+    };
+
+    var helpOpt = null;
+    self.addHelpOpt = function (opt, msg) {
+        helpOpt = opt;
+        self.describe(opt, msg || 'Show help');
+        return self;
+    };
+
     self.help = function () {
+        if (arguments.length > 0) {
+            return self.addHelpOpt.apply(self, arguments);
+        }
+
         var keys = Object.keys(
             Object.keys(descriptions)
             .concat(Object.keys(demanded))
@@ -397,6 +417,17 @@ function Argv (processArgs, cwd) {
 
         argv.$0 = self.$0;
 
+        Object.keys(argv).forEach(function(key) {
+            if (key === helpOpt) {
+                self.showHelp(console.log);
+                process.exit(0);
+            }
+            else if (key === versionOpt) {
+                console.log(version);
+                process.exit(0);
+            }
+        });
+
         if (demanded._ && argv._.length < demanded._.count) {
             if (demanded._.msg) {
                 fail(demanded._.msg);

test/usage.js

@@ -532,6 +532,46 @@ describe('usage', function () {
         ]);
     });
 
+    describe('help option', function () {
+        it('should display usage', function () {
+            var r = checkUsage(function () {
+                return yargs(['--help'])
+                    .demand(['y'])
+                    .help('help')
+                    .argv;
+            });
+            r.should.have.property('result');
+            r.result.should.have.property('_').with.length(0);
+            r.should.have.property('errors');
+            r.should.have.property('logs').with.length(1);
+            r.should.have.property('exit').and.be.ok;
+            r.logs.join('\n').split(/\n+/).should.deep.equal([
+                'Options:',
+                '  --help  Show help',
+                '  -y                 [required]',
+                ''
+            ]);
+        });
+    });
+
+    describe('version option', function () {
+        it('should display version', function () {
+            var r = checkUsage(function () {
+                return yargs(['--version'])
+                    .version('1.0.1', 'version', 'Show version number')
+                    .argv;
+            });
+            r.should.have.property('result');
+            r.result.should.have.property('_').with.length(0);
+            r.should.have.property('errors');
+            r.should.have.property('logs').with.length(1);
+            r.should.have.property('exit').and.be.ok;
+            r.logs.join('\n').split(/\n+/).should.deep.equal([
+                '1.0.1'
+            ]);
+        });
+    });
+
     it('should succeed when rebase', function () {
         yargs.rebase('/home/chevex', '/home/chevex/foo/bar/baz').should.equal('./foo/bar/baz');
         yargs.rebase('/home/chevex/foo/bar/baz', '/home/chevex').should.equal('../../..');