Re: [PATCH 0/2] xfsdump whitespace changes

[Dave Chinner <david@fromorbit.com>]

On Mon, Nov 05, 2018 at 11:15:34AM +0100, Jan Tulak wrote:
> On Fri, Nov 2, 2018 at 11:34 PM Dave Chinner <david@fromorbit.com> wrote:
> >
> > On Fri, Nov 02, 2018 at 12:43:18PM +0100, Jan Tulak wrote:
> > > On Fri, Nov 2, 2018 at 2:36 AM Dave Chinner <david@fromorbit.com> wrote:
> > > > On Thu, Nov 01, 2018 at 12:01:28PM +0100, Jan Tulak wrote:
> > > > However, it's is the same change as what you originally posted to a
> > >
> > > Yes, it is the same thing, with changes where I found something
> > > misaligned on top.
> > >
> > > > git tree, then it needs revision. basically, most of the change was
> > > > converting vertically aligned function call parameters to use tabs,
> > > > and that broke the vertical alignment.
> > >
> > > It is "s/    /\t/" limited to the beginning of the line.
> >
> > You mean 's/^    /\t/'?
> 
> Yes, but in multiple iterations to get \t, \t\t, \t\t\t, ...

Which is handled by this regex: 's/^\(\t*\)*    /\1\t/'

In this case, I'm using "*", which means "match zero or more of the
preceding expression" - which in this case is \t. That regex is
enclosed in \(...\) to group the result, which is then back
referenced in the output expression by \1 (first group backref).

Regexes are extremely and flexible once you've learnt how the
multiple object matching rules work.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com