Re: sed -i

On Thu, Mar 29, 2007 at 11:19:44AM +0300, Diomidis Spinellis wrote:
Yar Tikhiy 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.

Here is a couple of practical consequences:

- our sed won't act on a numeric range of lines in each file,
as in: sed -i '' 2,5d *, which may be counter-intuitive.
- our sed's line ranges can span file boundaries in -i mode.

If the second feature isn't important, I think we should use
a separate line space for each file edited in-line, which is
usually desired.

Comments?

P.S. Attached are a test script and outputs from it for our
sed and GNU sed as found in a Linux I have access to.


I believe the GNU interpretation of lines in -i makes sense.

Hurray! I've got a blessing from the author of BSD sed himself! :-)
Thank you!

May I take a bit more of your time?

I've started playing with the code and noticed another gray area.
Namely a `c' command won't print the text if having 2 addresses
with the 2nd address beyond the actual end of file. For example:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BEGIN
$ jot 9 |
sed '6,15c\
text
' test
1
2
3
4
5
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% END

Ditto with RE's, if the 2nd RE doesn't match any line:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BEGIN
$ jot 9 | sed '/6/,/15/c\
text
' test
1
2
3
4
5
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% END

If we've started to delete the pattern space, we should print the
text in place of it because `c' is for `change'. BSD and GNU seds
have this bug, but Solaris sed doesn't have it. Do you think we
should fix it, too?

Thanks!

--
Yar
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