Re: incorrect brace expansion when using default values

[Paul Jarc]

Mike Frysinger <vapier@gentoo.org> wrote:
> this little bit of code doesnt work right:
> foo() { echo "${1:-a{b,c}}" ; }

Brace expansion happens before parameter expansion (man bash,
EXPANSION).  So the first "}" ends the parameter expression, and the
second "}" isn't special.  The result of parameter expansion is not
subject to brace expansion.

> $ foo
> a{b,c}

This is correct.  "a{b,c" is the default value, and "}" follows the
parameter expression.

> $ foo 1
> a}

I get "1}".


paul