Re: [Help-bash] Escaping in backquote string in double quoted strings -- query about bash intent

[KHMan]

On 5/7/2019 9:07 PM, Greg Wooledge wrote:
> On Tue, May 07, 2019 at 08:52:02PM +0800, KHMan wrote:
> > If this is inappropriate for help-bash, I can repost it on the dev list. But
> > here I am only trying to understand the _intention_ of the code so that I
> > can code the appropriate highlighting fix -- it's really still a glorified
> > shell user's query.
>
> You might be better off looking at the POSIX spec that bash is trying to
> implement, rather than the implementation.
>
> http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_03
>
>    Within the backquoted style of command substitution, <backslash> shall retain
>    its literal meaning, except when followed by: '$', '`', or <backslash>. The
>    search for the matching backquote shall be satisfied by the first unquoted
>    non-escaped backquote; during this search, if a non-escaped backquote is
>    encountered within a shell comment, a here-document, an embedded command
>    substitution of the $(command) form, or a quoted string, undefined results
>    occur. A single-quoted or double-quoted string that begins, but does not end,
>    within the "`...`" sequence produces undefined results.
>
>    With the $(command) form, all characters following the open parenthesis to
>    the matching closing parenthesis constitute the command. Any valid shell
>    script can be used for command, except a script consisting solely of
>    redirections which produces unspecified results.
>
> Good luck trying to decipher that.

Already seen that in the ref man, that part in the ref man is 
quite similar. It doesn't say anything useful about \" behaviour 
in the nested scenario. The "`...`" there is just a single level 
`command` going by the style of the document.

So it's all undefined behaviour eh? Well, it sucks when users say 
the editor is buggy. So let me see if I can get a more substantial 
answer out of this list.


--
Cheers,
Kein-Hong Man (esq.)
Selangor, Malaysia