在图形界面中，执行拉取操作时，出现下面的错误。
You asked to pull from the remote 'origin', but did not specify
a branch. Because this is not the default configured remote
for your current branch, you must specify a branch on the command line.
解决办法：
Edit your .git/config
[branch "master"]
remote = origin
merge = refs/heads/master
Now you can simply git push and git pull.
参考地址：http://stackoverflow.com/questions/4847101/git-which-is-the-default-configured-remote-for-branch
