Re: [PATCH 1/3 v2] Add --blob-filter option to filter-branch.

> From: Jeff King <peff@peff.net>
> 
> This patch allows
> 
>   git filter-branch --blob-filter 'tr a-z A-Z'
> 
> However, it's _still_ horribly slow. Shell script is nice and flexible,
> but running a tight loop like this is just painful. I suspect
> filter-branch in something like perl would be a lot faster and just as
> flexible.
> 
> It is still much better performance than a tree filter, though:
> 
>   $ cd git && time git filter-branch --tree-filter '
>       find . -type f | while read f; do
>         tr a-z A-Z <"$f" >tmp
>         mv tmp "$f"
>       done
>     ' HEAD~10..HEAD
> 
>   real    4m38.626s
>   user    1m32.726s
>   sys     2m51.163s
> 
>   $ cd git && git filter-branch --blob-filter 'tr a-z A-Z' HEAD~10..HEAD
>   real    1m40.809s
>   user    0m36.822s
>   sys     1m14.273s
> 
> Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---