On Sun, Aug 31, 2025 at 07:49:57AM -0600, Stan Marsh wrote:
> (>> == pourko, > == Greg)
>
> >> Sorry, Greg, but this is no "compound" command, these are separate
> >> commands:
> >>
> >> $ shopt -s extglob; echo !(this)
>
> >That is another case where it fails, correct.
>
> >However, in your original email, you did indeed have the shopt inside
> >a compound command. That's why I phrased it the way I did.
>
> >If you wish, I'll add some additional verbosity to my original warning:
>
> > Turning on extglob changes how bash parses its input, and bash parses
> > line by line. In addition, bash has to parse compound commands (if,
> > for, while, functions and so on) as a whole.
>
> > The "shopt -s extglob" command must have been parsed and executed
> > BEFORE the parser tries to use extended globs.
>
> > Therefore, you cannot put "shopt -s extglob" on the same line, or
> > in the same compound command, as any extended glob.
>
> > I always advise people that if they're going to use extglob, it should
> > be done right up at the top of the script, either immediately below
> > the shebang, or after any mandatory comments that their boss demands
> > be present. Definitely before any function declarations or loops.
>
> This whole thread sounds like a tempest in a teapot; I mean, it is what it
> is, accept
> it and move on. Face the fact that the bash (and pretty much any other shell
> language; nothing specific to bash here) parser is line-oriented, even though
> it does
> have aspects of free-form languages (e.g., C). It is sort of a mishmash of
> the two.
>
> Incidentally, I sometimes run into this if I have an alias that I want to
> convert to a
> function. Assume foo is a (complicated) alias and you do:
>
> unalias foo;foo() { echo New definition for foo; }
>
> It no workie...
>
> But here's the thing: As far as I can tell, extglob is on-by-default - in all
> the
> versions of bash that I was able to test - so I don't understand why OP is
> messing
> around with turning it on and off. Or why Greg is talking about turning it
> on at the
> top of the script.
Are you referring to the fact that if the "==" or "!=" operater is used
within [[ ... ]], then the pattern is matched as if the extglob shell
option was enabled? (documented for the "[[" keyword)
... because the option is usually not enabled by default (unless some
shell library that you use enables it for you when you start the shell):
$ bash -c 'shopt | grep extglob'
extglob off
Cheers,
>
> Notes on the assertion above:
> 1) I do not have a compiled version of 5.3 release, but I tested on 5.3
> rc2 (the
> most recent version I have) and it was on-by-default.
> 2) The documentation seems to be out of step. Under the "shopt" command,
> extglob
> does not contain the usual notation of "This option is enabled by
> default".
>
> It should, shouldn't it?
>
> =================================================================================
> Please do not send me replies to my posts on the list.
> I always read the replies via the web archive, so CC'ing to me is unnecessary.
>
> When responding to my posts, please try to refrain from giving bureaucratic
> answers.
> If you have nothing useful to say, then just click Next and go on.
--
Matti Andreas Kähäri
Uppsala, Sweden
.
