Your branch is ahead of 'origin/master' by 1 commit

        如果只在本地修改，还没有commit，那么用git status, 打印信息为：

# On branch master
# Changes not staged for commit:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#    modified:   conf/gitolite.conf
#
no changes added to commit (use "git add" and/or "git commit -a")

        commit之后，用git status，打印信息为：

# On branch master
# Your branch is ahead of 'origin/master' by 1 commit.
#
nothing to commit (working directory clean)

说明没有文件需要commit，但是本地仓库 有一个commit ahead原来的master，就是本地仓库有一个提交，比远程仓库要先进一个commit。git push origin master之后，再用git staus，打印信息为：

# On branch master
nothing to commit (working directory clean)