[Tutor] delete strings from specificed words

[YU Bo]

Hi,

I am learning python to reslove issue,which make happy:)

But, i am facing an interesting question.I have no idea to deal with it.

The text i will working as follow:

```text

[PATCH] perf tools: Fix copyfile_offset update of output offset

We need to increase output offset in each iteration,
not decrease it as we currently do.

I guess we were lucky to finish in most cases in first
iteration, so the bug never showed. However it shows a
lot when working with big (~4GB) size data.

Link: http://lkml.kernel.org/n/tip-f4az7t2nxjbjz5tqrv83z64e@xxxxxxxxxxxxxx
Signed-off-by: Jiri Olsa <jolsa at xxxxxxxxxx>
---
 tools/perf/util/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index a789f952b3e9..443892dabedb 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -210,7 +210,7 @@ static int copyfile_offset(int ifd, loff_t off_in, int ofd, loff_t off_out, u64

 		size -= ret;
 		off_in += ret;
-		off_out -= ret;
+		off_out += ret;
 	}
 	munmap(ptr, off_in + size);

--
2.13.6

```
In fact, this is a patch from lkml,my goal is to design a kernel podcast
for myself to focus on what happened in kernel. I have crawled the text
with python and want to remove strings from *diff --git*, because reading
the git commit above, i have a shape in head.

I have tried split(), replace(), but i have no idea to deal with it.

I will  appericate if you have any idea.

Thanks!