Re: !(.pattern) can match . and .. if dotglob is enabled

[Chet Ramey]

On 6/6/21 6:31 AM, Ilkka Virta wrote:
>     Can you write a set of rules that encapsulates what you would like to see?
>     Or can the group?
>
>
> I think it's a bit weird that !(.foo) can match . and .. when * doesn't.
>
> The other means roughly "anything here", and the other means "anything but 
> .foo here",
> so having the latter match things the former doesn't is surprising.

Yes, that's essentially where we ended up.

> Personally, I'd just want an option to always make . and .. hidden from 
> globs. 

You can use GLOBIGNORE for this, but you have to do a little more work.

> Or rather,
> to never generate . or .. as a pathname component via globbing.

I don't think it's useful -- and it's certainly incompatible -- to make
an explicit pattern like `.?' ignore `..'.


> For what it's worth, Zsh, mksh and fish seem to always hide . and .. , and 
> at least Zsh does
> that even with (.|..) or @(.|..) .

Do they have the equivalent of `dotglob'?

And if we want to play this game, ksh93, dash, yash, and the BSD shells
all match `.' and `..' with patterns like `.*' and `.?'.

> I tried to achieve that via GLOBIGNORE=.:.. , but that has the problem that 
> it forces dotglob
> on, and looks at the whole resulting path, so ./.* still gives ./. and ./.. 
> . Unless you use
> GLOBIGNORE=.:..:*/.:*/.. etc., but repeating the same for all different 
> path lengths gets a bit
> awkward.

Yes, that's the `more work' part. You have to tune it to your needs.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/