sed -i

[Yar Tikhiy]

On Mon, Mar 26, 2007 at 08:57:14PM +0530, Joseph Koshy wrote:
> >Recently noticed that our sed(1) differs from its GNU
> >analog in that in -i mode it considers all files as a
> >single sequence of lines while the latter treats each file
> >independently.  The in-line mode isn't in POSIX, so it isn't
> >really clear which way is correct.
> 
> Aren't sed's addresses required to be cumulative across its
> input files?
> 
> http://www.opengroup.org/onlinepubs/009695399/utilities/sed.html

That makes sense for filter mode because it's equvalent to
concatenating the files in advance:

	cat files ... | sed expression

OTOH, in-place mode selected by a -i option can be seen as follows:

	for f in files ...; do
		sed expression < $f > $f.tmp && mv $f $f.bak && mv $f.tmp $f
	done

I.e., each file preserves its individuality.  This can be at logical
conflict with cumulative addresses across all files.

-- 
Yar