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Re: namerefs and environment variable names with subscripts


From: Chet Ramey
Subject: Re: namerefs and environment variable names with subscripts
Date: Wed, 18 Jul 2018 14:51:53 -0400
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.9.1

On 7/17/18 4:44 PM, Grisha Levit wrote:
> The following commands:
> 
>     declare -n r=v[0]
>     v=(X); r=Y
>     declare -p ${!v*}
>     printf "%s: <%s>\n" "r" "$r" "v" "$v"
> 
> Will normally produce the following output:
> 
>     declare -a v=([0]="Y")
>     r: <Y>
>     v: <Y>
> 
> However, if we start bash with `v[0]' already in the environment, such as 
> with:
> 
>     env 'v[0]=' $BASH
> 
> The behavior changes, and the output is:
> 
>     declare -a v=([0]="X")
>     declare -x v[0]="Y"
>     r: <Y>
>     v: <X>
> 
> I would expect namerefs to ignore any variables with the literal name
> `v[0]' in the environment rather than follow them.

Thanks. Bash needs to better segregate environment variables that aren't
valid shell identifiers.

Chet

-- 
``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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