resolves tj#560 respect custom name for version option

index.js

@@ -774,7 +774,7 @@ Command.prototype.opts = function() {
 
   for (var i = 0 ; i < len; i++) {
     var key = this.options[i].attributeName();
-    result[key] = key === 'version' ? this._version : this[key];
+    result[key] = key === this._versionOptionName ? this._version : this[key];
   }
   return result;
 };
@@ -857,8 +857,10 @@ Command.prototype.version = function(str, flags) {
   if (0 == arguments.length) return this._version;
   this._version = str;
   flags = flags || '-V, --version';
+  var longOptIndex = flags.indexOf('--')
+  this._versionOptionName = ~longOptIndex ? flags.substr(longOptIndex + 2) : 'version'
   this.option(flags, 'output the version number');
-  this.on('option:version', function() {
+  this.on('option:' + this._versionOptionName, function() {
     process.stdout.write(str + '\n');
     process.exit(0);
   });

test/test.options.version.custom.js

@@ -0,0 +1,20 @@
+var program = require('../')
+  , should = require('should');
+
+var capturedExitCode, capturedOutput, oldProcessExit, oldProcessStdoutWrite;
+
+program.version('0.0.1', '-r, --revision');
+
+['-r', '--revision'].forEach(function (flag) {
+  capturedExitCode = -1;
+  capturedOutput = '';
+  oldProcessExit = process.exit;
+  oldProcessStdoutWrite = process.stdout.write;
+  process.exit = function (code) { capturedExitCode = code; }
+  process.stdout.write = function(output) { capturedOutput += output; }
+  program.parse(['node', 'test', flag]);
+  process.exit = oldProcessExit;
+  process.stdout.write = oldProcessStdoutWrite;
+  capturedOutput.should.equal('0.0.1\n');
+  capturedExitCode.should.equal(0);
+})

test/test.options.version.js

@@ -0,0 +1,20 @@
+var program = require('../')
+  , should = require('should');
+
+var capturedExitCode, capturedOutput, oldProcessExit, oldProcessStdoutWrite;
+
+program.version('0.0.1');
+
+['-V', '--version'].forEach(function (flag) {
+  capturedExitCode = -1;
+  capturedOutput = '';
+  oldProcessExit = process.exit;
+  oldProcessStdoutWrite = process.stdout.write;
+  process.exit = function (code) { capturedExitCode = code; }
+  process.stdout.write = function(output) { capturedOutput += output; }
+  program.parse(['node', 'test', flag]);
+  process.exit = oldProcessExit;
+  process.stdout.write = oldProcessStdoutWrite;
+  capturedOutput.should.equal('0.0.1\n');
+  capturedExitCode.should.equal(0);
+})