On 9/30/20 12:28 AM, Jason Miller wrote:
> Gentoo linux, GNU bash, version 5.0.18(1)-release (x86_64-pc-linux-gnu)
>
> On the above vesion of bash, the following script will not run the echo
> command
> and print an error. On bash 4.4 it appears to treat the ${!foo} the same as
> expanding an unset variable and thus outputs "bar":
>
> unset foo
> echo ${!foo} bar
This is the result of
https://lists.gnu.org/archive/html/bug-bash/2016-11/msg00123.html
I explained the reasoning in
https://lists.gnu.org/archive/html/bug-bash/2016-11/msg00165.html
The basic idea is that indirect expansion is just a string substitution,
so indirecting an unset variable is the logically same thing as ${},
which is an expansion error.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU [email protected] http://tiswww.cwru.edu/~chet/
