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Re: [Help-bash] Escaping in backquote string in double quoted strings --
Re: [Help-bash] Escaping in backquote string in double quoted strings -- query about bash intent
Tue, 7 May 2019 21:27:37 +0800
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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.
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.
Kein-Hong Man (esq.)