add git show-branch command (#197)

* add git show-branch command

* add doc

* cleanup log (remove quiet mode)

README.md

@@ -539,6 +539,21 @@ git.branch('development', function (err) {
 });
 ```
 
+### git.showBranch(opt, cb)
+`git show-branch <opt>`
+
+Show branches and their commits
+
+`opt`: Object (optional) `{args: 'options'}`
+
+`cb`: function, passed err if any
+
+```js
+git.showBranch({'args': '--list -a'}, function (err) {
+  //if (err) ...
+});
+```
+
 ### git.checkout(branch, opt, cb)
 `git checkout <new branch name>`
 

index.js

@@ -23,6 +23,7 @@
  * @property {function} reset           {@link module:gulp-git/lib/reset}
  * @property {function} revParse        {@link module:gulp-git/lib/revParse}
  * @property {function} rm              {@link module:gulp-git/lib/rm}
+ * @property {function} showBranch      {@link module:gulp-git/lib/showBranch}
  * @property {function} stash           {@link module:gulp-git/lib/stash}
  * @property {function} status          {@link module:gulp-git/lib/status}
  * @property {function} tag             {@link module:gulp-git/lib/tag}

lib/showBranch.js

@@ -0,0 +1,23 @@
+'use strict';
+
+var log = require('fancy-log');
+var exec = require('child_process').exec;
+
+module.exports = function (opt, cb) {
+  if (!cb && typeof opt === 'function') {
+    // optional options
+    cb = opt;
+    opt = {};
+  }
+  if (!cb || typeof cb !== 'function') cb = function () {};
+  if (!opt) opt = {};
+  if (!opt.cwd) opt.cwd = process.cwd();
+  if (!opt.args) opt.args = ' ';
+
+  var cmd = 'git show-branch ' + opt.args;
+  return exec(cmd, {cwd: opt.cwd}, function(err, stdout, stderr) {
+    if (err) return cb(err);
+    log(stdout, stderr);
+    cb(null, stdout);
+  });
+};