Re: how to track the history of a line in a file

> On Fri, 2 Jan 2009, Jeff King wrote:
>
>> The tricky thing here is what is "this line"? Using the line number
>> isn't right, since it will change based on other content coming in and
>> out of the file. You can keep drilling down by reblaming parent commits,
>> but remember that each time you do that you are manually looking at the
>> content and saying "Oh, this is the line I am still interested in." So I
>> a script would have to correlate the old version and new version of the
>> line and realize how to follow the "interesting" thing.
>> 
>> In your case, I think you want to see any commit in Makefile which
>> changed a line with SUBLEVEL in it. Which is maybe easiest done as:
>>
>>  git log -z -p Makefile |
>>    perl -0ne 'print if /\n[+-]SUBLEVEL/' |
>>    tr '\0' '\n'
>> 
>> and is pretty fast. But obviously we're leveraging some content-specific
>> knowledge about what's in the Makefile.
>
> Ok, I hacked togeather a quick bash script to try this
>

> the problem that this has is that line 3 of $COMMIT may not be line 3 of 
> $COMMIT^, and if they aren't it ends up hunting down the wrong data
>
> either that or I am not understanding the output of git blame properly (also 
> very possible)