bug#73598: Acknowledgement (bug in sed Invalid preceding regular expression)

[Peter Smulders]

Some further observations regarding the behaviour of regular expressions 
in 'sed'

as noticed before  the following is not accepted

$ echo ****somestring | sed s/\*\*\*\*//
sed: -e expression #1, char 8: Invalid preceding regular expression

but the following does

$ echo ****somestring | sed s/\\*\\*\\*\\*//
somestring

However, even this does not work anymore if the command is surrounded by 
backquotes.

e.g.
$ name=`echo ****some string | sed s/\\*\\*\\*\\*//`
sed: -e expression #1, char 8: Invalid preceding regular expression

On the other hand the equivalent using $() is ok:
$ name=$(echo ****some string | sed s/\\*\\*\\*\\*//)
$ echo $name
some string


On 2-10-2024 16:50, Peter Smulders wrote:
> I think I know already what is the matter. For to work properly double 
> escapes are needed, i.e.
>
>  echo ****some string | sed s/\\*\\*\\*\\*//
>
> But I still find it strange ...
>
> On 2-10-2024 15:00, GNU bug Tracking System wrote:
> > Thank you for filing a new bug report with debbugs.gnu.org.
> >
> > This is an automatically generated reply to let you know your message
> > has been received.
> >
> > Your message is being forwarded to the package maintainers and other
> > interested parties for their attention; they will reply in due course.
> >
> > Your message has been sent to the package maintainer(s):
> > bug-sed@gnu.org
> >
> > If you wish to submit further information on this problem, please
> > send it to 73598@debbugs.gnu.org.
> >
> > Please do not send mail to help-debbugs@gnu.org unless you wish
> > to report a problem with the Bug-tracking system.