常见错误
1.You have unmerged files
$ git status
On branch master
You have unmerged paths.
(fix conflicts and run "git commit")
Unmerged paths:
(use "git add <file>..." to mark resolution)
both modified: index.html
no changes added to commit (use "git add" and/or "git commit -a")</file>解决方案：查看发生冲突的文件，手动修改后commit，通过 git mergetool 可以看到图形化的界面，便于直观的理解。
2.add操作warning
$ git add -A
warning: LF will be replaced by CRLF in file
The file will have its original line endings in your working directory.</code>原因：Linux平台下的换行符是 LF，而Windows下则是 CRLF，所以当你再 Windows 保存文件时候，换行符会被保存为
建议：统一换行符为 LF
解决方案：Git 命令行输入如下命令，禁止自动转换换行符
git config --global core.autocrlf false
3.git pull 失败
You have not concluded your merge (MERGE_HEAD exists).
Please, commit your changes before you can merge.原因：之前进行 Pull 操作时自动合并失败，和原文件有冲突
解决方案：取消 Pull 操作然后手动合并
取消合并：
git merge --abort
git reset --merge
解决冲突 重新 add and commit 拉取分支然后合并，git pull
4.push error
$ git push origin master
To john@githost:simplegit.git
! [rejected] master -> master (non-fast forward)
error: failed to push some refs to 'john@githost:simplegit.git'原因：之前有人进行过提交，本地项目并不是最新的，在提交之前，必须合并当前分支至最新
解决方案：git merge origin/master，当你直接在master分支的时候，可以git pull，相当于git fetch + git merge
5.checkout:unable to create '/path/project/.git/index.lock'
Git - fatal: Unable to create '/path/my_project/.git/index.lock': File exists.解决方案：rm -f ./.git/index.lock
总结
有一条准则谨记，任何命令中带有 –hard 参数的都谨慎执行，很有可能造成不可逆的损失。