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Re: [doc] missing doc about :+ vs + expansion


From: Chet Ramey
Subject: Re: [doc] missing doc about :+ vs + expansion
Date: Mon, 25 Mar 2019 09:04:47 -0400
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.6.0

On 3/25/19 6:19 AM, Christophe Lyon wrote:
> Hi,
> 
> I think I've noticed a bit of explanation missing in the documentation
> about parameter expansion.
> 
> bash supports :+ and + expansion, but 'man bash' describes the former only.
> This is also true for the similar expansions (:-, :=, :?)

"When not performing substring expansion,  using  the  forms  documented
below  (e.g.,  :-),  bash  tests for a parameter that is unset or null.
Omitting the colon results in a test  only  for  a  parameter  that  is
unset."

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



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