Re: Not missing, but very hard to see (was Re: Backslash missing in brace expansion)

[L A Walsh]

On 2019/12/12 13:01, Ilkka Virta wrote:
> On 12.12. 21:43, L A Walsh wrote:
>   
> > On 2019/12/06 14:14, Chet Ramey wrote:
> >
> > Seems very hard to print out that backquote though.  Closest I got
> > was bash converting it to "''":
> >     
>
> The backquote is in [6], and the backslash disappears, you just get the 
> pair of quotes in [2] because that's how printf %q outputs an empty string.
>   
-----

   I'm sorry, but you are mistaken.

   The characters from 'Z' (0x5A) through 'z' (0x61) are:

0x5A 0x5B 0x5C 0x5D 0x5E 0x5F 0x60 0x61
Z    [    \    ]     ^   _     `    a

the backslash comes between the two square brackets.

Position [6] is the "Grave Accent" (or backquote).

It is quoted properly.

As for %q printing an empty string for 0x5C

        "%q" causes  printf to output the corresponding argument in a
        format that can be reused as shell input.

   For that string to be empty would mean there is no character at hex
value 0x5C (unicode U+005C), which isn't so.

>   
> > >  read -r -a a< <(printf "%q " {Z..a})
> > >  my -p a
> > >       
> > declare -a a=([0]="Z" [1]="\\[" [2]="''" [3]="\\]" [4]="\\^" [5]="_" 
> > [6]="\\\`" [7]="a")
> >     
>
>
>