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Re: . and .. are included where they were excluded before

Subject: Re: . and .. are included where they were excluded before
Date: Tue, 26 Jan 2021 20:27:44 +0000
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.6.1

On 26/01/2021 19:34, gregrwm wrote:

          . and .. are excluded from @(?|.?) in
          bash 4.2.46(2)-release (CentOS 7.8), but are included in
          bash 4.4.19(1)-release (CentOS 8.2) and
          bash 5.0.17(1)-release (Ubuntu 20.04/focal).

According to the manual, "[t]he filenames ‘.’ and ‘..’ must always be
matched explicitly even if dotglob is set." I don't see any subsequent
text that overrules this for extended globs.


Indeed, nor should you...  @(?|.?) should never ignore '..', owing to the
presence of the .? pattern which explictly matches...

Kerin Millar

you're calling .. an explicit match to .?

Yes, I am. It's in line with the various sh(1) implementations also.

What makes the pathnames . and .. special is that a glob must begin with a literal dot to match them by way of pathname expansion. That much, I think, is explained adequately by the manual. Enabling dotglob doesn't affect this constraint.

I'm still worried about some of the curious results shown by your original post but I haven't had a chance to test the same platforms yet. I can easily imagine CentOS 7.2 being buggy; not so much in the case of the other two operating systems that you mention.

i'd interpret explicit match to mean .. wouldn't match anything other than
itself (notwithstanding it's been otherwise for over a decade)

In isolation, .. isn't a glob. It won't be subjected to pathname expansion and thus, there's nothing to even 'match'. Rather, it will always be taken literally.

Still, I can see how the import of the present wording might not be fully understood upon first reading. Perhaps it could be tweaked a little.

          but that's a bit askew from what actually interests me.  if i had
my druthers, there would be an option to set so . and .. would never
any (sub)glob other than their literal selves (even with dotglob set).

As Kerin Millar said, you can use GLOBIGNORE for this.

indeed that's exactly what i was looking for, thank you lawrence, kerin,
and chet

Kerin Millar

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