如何在 git 里查找哪一个 commit 删除了代码的一行

http://blog.csdn.net/robertsong2004/article/details/46892047

If you know the contents of the line, this is an ideal use case for:
git log -S path/to/file
which shows you commits which introduce or remove an instance of that string. There's also the -G which does the same thing with regular expressions! See man Git-log and search for the -G and -S options, or pickaxe (the friendly name for these features) for more information.
The -S option is actually mentioned in the header of the git-blame manpage too, in the description section, where it gives an example using git log -S....