Re: [Help-bash] Separation of compound commands

[Chet Ramey]

On 3/14/17 12:24 PM, D630 wrote:
> Why does A work, but B doesn't?
> 
> # A
> { { :; } }
> if :; then if :; then :; fi fi
> { (:) }
> 
> # B
> { (()) }
> { [[ 1 ]] }

The stuff between the braces has to be a compound_list. A compound_list
needs a terminator (`&', `;', `\n', etc.).  The (( and [[ commands aren't
specified as being terminated by operators in the bash grammar; they're
more like commands that begin and end with reserved words.  When you read
a reserved word like ]] or )), you are not in a position to read another
reserved word (`}' is a reserved word, not an operator), so you need a
separator, which in this case is the list terminator.

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