How to print an octal value's corresponding UTF-8 character in bash?

Question

I expected printf %s '\<octal_character_value>' to do the trick, but it doesn't:

printf %s '\101'

Outputs:

\101

Answer 1

Presumably you want %b. From help printf:

In addition to the standard format specifications described in printf(1),
printf interprets:

  %b    expand backslash escape sequences in the corresponding argument

And:

$ printf "%b\n" '\101'
A

I don't know if it works for Unicode characters in general.

Answer 2

You can use Awk:

$ awk 'BEGIN {print "\107"}'
G

Or the awk Velour library:

$ velour -n 'print n_chr(+n_baseconv(107, 8, 10))'
G

Answer 3

It works with unicode as long as you type out the byte.

$ gprintf '\353\200\200' | odview
0000000           8421611

          ""  **  **

          353 200 200

           ?  80  80

          235 128 128

           eb  80  80

                  8421611
0000003

The %b operator isn't necessary (as long as your octals aren't \0NNN form, at least in the macOS 11.5 bash3 built-in, the macOS BSD-UNIX printf, and also gnu-printf 8.32.

This character is U+B000 (n=45,056). The decomposed one is more verbose but works the same

gprintf '\341\204\201\341\205\260\341\206\267' | odview
0000000        3783361761      2262937733             183

          ᄁ  **  **   ᅰ  **  **   ᆷ  **  **

          341 204 201 341 205 260 341 206 267

           ?  84  81   ?  85   ?   ?  86   ?

          225 132 129 225 133 176 225 134 183

           e1  84  81  e1  85  b0  e1  86  b7

               -511605535     -2032029563             183