On Mon, Feb 10, 2025 at 15:20:55 +0100, Phi Debian wrote:
> If 'best *general*' refer to the shortest line noise does
>
> $((${i/?([-+])/&10#}))
>
> Qualify for better than best ? :-) if so you may add in your web bible
> don't forget to mention the inventor :-)
Can you please explain *how* this is working in older bash versions?
According to the CHANGES file, the processing of `&' by patsub_replacement
is new in bash 5.2. And yet:
hobbit:~$ bash-2.05b
bash-2.05b: /home/greg/.bashrc: line 95: syntax error in conditional
expression: unexpected token `('
bash-2.05b: /home/greg/.bashrc: line 95: syntax error near `+(['
bash-2.05b: /home/greg/.bashrc: line 95: ` if [[ $letters != +([A-Z]) ]];
then'
hobbit:~$ shopt | grep extglob
extglob off
hobbit:~$ var=-023
hobbit:~$ echo "$(( ${var/?([-+])/&10#} ))"
-19
So, not only is the & being respected, but the extended glob is also
working, despite extglob being visibly disabled. Not to mention, this
version is decades older than the patsub_replacement feature, at least
according to the documentation we have.
