Re: Inconsistent quote and escape handling in substitution part of parameter expansions.

[John Kearney]

It isn't just the quote removal that is confusing.

The escape character is also not removed and has its special meaning.


and this also confuses me
take the following 2 cases
echo ${aaaaa:-$'\''}
'
echo "${aaaaa:-$'\''}"
bash: bad substitution: no closing `}' in "${aaaaa:-'}"


and take the following 3 cases
echo "${aaaaa:-$(echo $'\'')}"
bash: command substitution: line 38: unexpected EOF while looking for
matching `''
bash: command substitution: line 39: syntax error: unexpected end of file

echo ${aaaaa:-$(echo $'\'')}
'
echo "${aaaaa:-$(echo \')}"
'

This can not be logical behavior.

On 02/29/2012 11:26 PM, Chet Ramey wrote:
> On 2/28/12 10:52 AM, John Kearney wrote:
>> Actually this is something that still really confuses me as
>> well.
> 
> The key is that bash doesn't do quote removal on the `string' part
> of the "${param/pat/string}" expansion.  The double quotes are key;
> quote removal happens when the expansion is unquoted.
> 
> Double quotes are supposed to inhibit quote removal, but bash's
> hybrid behavior of allowing quotes to escape characters but not
> removing them is biting us here.
>