From: Jim Hranicky <jfh@...>
Date: 2009-02-17T01:49:24+09:00
Subject: [ruby-core:22186] Re: Dir.glob and duplicates?

Thomas Enebo wrote:

> ls {/Users,/Users,/Users}/enebo
> 
> It is a good question why many impls all decided to copy this behavior, 
> but it is there and I am guessing the reason for supporting it is 
> "principle of least surprise" (and yes I find this somewhat ironic).
> 
> -Tom
> 
> PS- For the record globbing with {} is one of my favorite shortcuts ls 
> -l foo{,~}, but I have never used the dup feature.  So this is news to 
> me until this thread :)

Interesting -- being a zsh user I've always thought of braces differently
than other shell globbing because braces simply evaluate to what you specify
regardless of whether there are any files that match:

   % echo {a,b,c}
   a b c

   % echo a* b* c*
   zsh: no matches found: a*

This allows for cool things like

   % mv /some/horribly/long/pathname/Id/hate/to/have/to/type/twice{,.bak}

bash works a little differently though with wildcards, which I assume to
be more like the original Bourne shell:

   [jfh@kestrel e]$ echo {a,b,c}
   a b c
   [jfh@kestrel e]$ echo a* b* c*
   a* b* c*

tcsh seems to work like zsh.

I think if ruby globbing is to mimic shell globbing, dups would have to
be allowed when and only when braces are specified.

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| Jim Hranicky, Security Engineer                    UF InfoSec Team |
| E202 SSRB                                     Phone (352) 392-2061 |
|                              jfh@ufl.edu                           |
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