Are still control characters used nowdays?
https://en.wikipedia.org/wiki/Control_character
user@minipc1:~/fred$ od -tu1 test.txt
0000000 48 48 32 104 101 108 108 111 0 32 104 101 108 108 111 10
0000020 48 49 32 104 101 108 108 111 1 32 104 101 108 108 111 10
0000040 48 50 32 104 101 108 108 111 2 32 104 101 108 108 111 10
0000060 48 51 32 104 101 108 108 111 3 32 104 101 108 108 111 10
0000100 48 52 32 104 101 108 108 111 4 32 104 101 108 108 111 10
0000120 48 53 32 104 101 108 108 111 5 32 104 101 108 108 111 10
0000140 48 54 32 104 101 108 108 111 6 32 104 101 108 108 111 10
0000160 48 55 32 104 101 108 108 111 7 32 104 101 108 108 111 10
0000200 48 56 32 104 101 108 108 111 8 32 104 101 108 108 111 10
0000220 48 57 32 104 101 108 108 111 9 32 104 101 108 108 111 10
0000240 49 48 32 104 101 108 108 111 10 32 104 101 108 108 111 10
0000260 49 49 32 104 101 108 108 111 11 32 104 101 108 108 111 10
0000300 49 50 32 104 101 108 108 111 12 32 104 101 108 108 111 10
0000320 49 51 32 104 101 108 108 111 13 32 104 101 108 108 111 10
0000340 49 52 32 104 101 108 108 111 14 32 104 101 108 108 111 10
0000360 49 53 32 104 101 108 108 111 15 32 104 101 108 108 111 10
0000400 49 54 32 104 101 108 108 111 16 32 104 101 108 108 111 10
0000420 49 55 32 104 101 108 108 111 17 32 104 101 108 108 111 10
0000440 49 56 32 104 101 108 108 111 18 32 104 101 108 108 111 10
0000460 49 57 32 104 101 108 108 111 19 32 104 101 108 108 111 10
0000500 50 48 32 104 101 108 108 111 20 32 104 101 108 108 111 10
0000520 50 49 32 104 101 108 108 111 21 32 104 101 108 108 111 10
0000540 50 50 32 104 101 108 108 111 22 32 104 101 108 108 111 10
0000560 50 51 32 104 101 108 108 111 23 32 104 101 108 108 111 10
0000600 50 52 32 104 101 108 108 111 24 32 104 101 108 108 111 10
0000620 50 53 32 104 101 108 108 111 25 32 104 101 108 108 111 10
0000640 50 54 32 104 101 108 108 111 26 32 104 101 108 108 111 10
0000660 50 55 32 104 101 108 108 111 27 32 104 101 108 108 111 10
0000700 50 56 32 104 101 108 108 111 28 32 104 101 108 108 111 10
0000720 50 57 32 104 101 108 108 111 29 32 104 101 108 108 111 10
0000740 51 48 32 104 101 108 108 111 30 32 104 101 108 108 111 10
0000760 51 49 32 104 101 108 108 111 31 32 104 101 108 108 111 10
0001000 49 50 55 104 101 108 108 111 127 32 104 101 108 108 111 10
Can be found here: https://github.com/defdefred/control-characters/raw/main/test.txt
user@minipc1:~/fred$ cat test.txt
00 hello hello
01 hello hello
02 hello hello
03 hello hello
04 hello hello
05 hello hello
06 hello hello
07 hello hello
08 hell hello
09 hello hello
10 hello
hello
11 hello
hello
12 hello
hello
hellolo
14 hello hello
15 hello hello
16 hello hello
17 hello hello
18 hello hello
19 hello hello
20 hello hello
21 hello hello
22 hello hello
23 hello hello
24 hello hello
25 hello hello
26 hello hello
27 hellohello
28 hello hello
29 hello hello
30 hello hello
31 hello hello
127hello hello
8 to 13 + 27 seems to be interpreted by cat
user@minipc1:~/fred$ cat -vT test.txt
00 hello^@ hello
01 hello^A hello
02 hello^B hello
03 hello^C hello
04 hello^D hello
05 hello^E hello
06 hello^F hello
07 hello^G hello
08 hello^H hello
09 hello^I hello
10 hello
hello
11 hello^K hello
12 hello^L hello
13 hello^M hello
14 hello^N hello
15 hello^O hello
16 hello^P hello
17 hello^Q hello
18 hello^R hello
19 hello^S hello
20 hello^T hello
21 hello^U hello
22 hello^V hello
23 hello^W hello
24 hello^X hello
25 hello^Y hello
26 hello^Z hello
27 hello^[ hello
28 hello^\ hello
29 hello^] hello
30 hello^^ hello
31 hello^_ hello
127hello^? hello
Only 10 is interpreted by cat -vT
user@minipc1:~/fred$ od -a test.txt
0000000 0 0 sp h e l l o nul sp h e l l o nl
0000020 0 1 sp h e l l o soh sp h e l l o nl
0000040 0 2 sp h e l l o stx sp h e l l o nl
0000060 0 3 sp h e l l o etx sp h e l l o nl
0000100 0 4 sp h e l l o eot sp h e l l o nl
0000120 0 5 sp h e l l o enq sp h e l l o nl
0000140 0 6 sp h e l l o ack sp h e l l o nl
0000160 0 7 sp h e l l o bel sp h e l l o nl
0000200 0 8 sp h e l l o bs sp h e l l o nl
0000220 0 9 sp h e l l o ht sp h e l l o nl
0000240 1 0 sp h e l l o nl sp h e l l o nl
0000260 1 1 sp h e l l o vt sp h e l l o nl
0000300 1 2 sp h e l l o ff sp h e l l o nl
0000320 1 3 sp h e l l o cr sp h e l l o nl
0000340 1 4 sp h e l l o so sp h e l l o nl
0000360 1 5 sp h e l l o si sp h e l l o nl
0000400 1 6 sp h e l l o dle sp h e l l o nl
0000420 1 7 sp h e l l o dc1 sp h e l l o nl
0000440 1 8 sp h e l l o dc2 sp h e l l o nl
0000460 1 9 sp h e l l o dc3 sp h e l l o nl
0000500 2 0 sp h e l l o dc4 sp h e l l o nl
0000520 2 1 sp h e l l o nak sp h e l l o nl
0000540 2 2 sp h e l l o syn sp h e l l o nl
0000560 2 3 sp h e l l o etb sp h e l l o nl
0000600 2 4 sp h e l l o can sp h e l l o nl
0000620 2 5 sp h e l l o em sp h e l l o nl
0000640 2 6 sp h e l l o sub sp h e l l o nl
0000660 2 7 sp h e l l o esc sp h e l l o nl
0000700 2 8 sp h e l l o fs sp h e l l o nl
0000720 2 9 sp h e l l o gs sp h e l l o nl
0000740 3 0 sp h e l l o rs sp h e l l o nl
0000760 3 1 sp h e l l o us sp h e l l o nl
0001000 1 2 7 h e l l o del sp h e l l o nl
user@minipc1:~/fred$ od -c test.txt
0000000 0 0 h e l l o \0 h e l l o \n
0000020 0 1 h e l l o 001 h e l l o \n
0000040 0 2 h e l l o 002 h e l l o \n
0000060 0 3 h e l l o 003 h e l l o \n
0000100 0 4 h e l l o 004 h e l l o \n
0000120 0 5 h e l l o 005 h e l l o \n
0000140 0 6 h e l l o 006 h e l l o \n
0000160 0 7 h e l l o \a h e l l o \n
0000200 0 8 h e l l o \b h e l l o \n
0000220 0 9 h e l l o \t h e l l o \n
0000240 1 0 h e l l o \n h e l l o \n
0000260 1 1 h e l l o \v h e l l o \n
0000300 1 2 h e l l o \f h e l l o \n
0000320 1 3 h e l l o \r h e l l o \n
0000340 1 4 h e l l o 016 h e l l o \n
0000360 1 5 h e l l o 017 h e l l o \n
0000400 1 6 h e l l o 020 h e l l o \n
0000420 1 7 h e l l o 021 h e l l o \n
0000440 1 8 h e l l o 022 h e l l o \n
0000460 1 9 h e l l o 023 h e l l o \n
0000500 2 0 h e l l o 024 h e l l o \n
0000520 2 1 h e l l o 025 h e l l o \n
0000540 2 2 h e l l o 026 h e l l o \n
0000560 2 3 h e l l o 027 h e l l o \n
0000600 2 4 h e l l o 030 h e l l o \n
0000620 2 5 h e l l o 031 h e l l o \n
0000640 2 6 h e l l o 032 h e l l o \n
0000660 2 7 h e l l o 033 h e l l o \n
0000700 2 8 h e l l o 034 h e l l o \n
0000720 2 9 h e l l o 035 h e l l o \n
0000740 3 0 h e l l o 036 h e l l o \n
0000760 3 1 h e l l o 037 h e l l o \n
0001000 1 2 7 h e l l o 177 h e l l o \n
0, 7 to 13 seems to have special meaning for unix.
00 hello^@ hello↲
01 hello^A hello↲
02 hello^B hello↲
03 hello^C hello↲
04 hello^D hello↲
05 hello^E hello↲
06 hello^F hello↲
07 hello^G hello↲
08 hello^H hello↲
09 hello→→ hello↲
10 hello↲
hello↲
11 hello^K hello↲
12 hello^L hello↲
13 hello^M hello↲
14 hello^N hello↲
15 hello^O hello↲
16 hello^P hello↲
17 hello^Q hello↲
18 hello^R hello↲
19 hello^S hello↲
20 hello^T hello↲
21 hello^U hello↲
22 hello^V hello↲
23 hello^W hello↲
24 hello^X hello↲
25 hello^Y hello↲
26 hello^Z hello↲
27 hello^[ hello↲
28 hello^\ hello↲
29 hello^] hello↲
30 hello^^ hello↲
31 hello^_ hello↲
127hello^? hello↲
Only 9 and 10 are interpreted by vim.
TAB can be managed with set listchars and set tabstop.
set encoding=utf-8↲
set showbreak=↪↲
set listchars=tab:→→,eol:↲,nbsp:␣,trail:•,extends:⟩,precedes:⟨↲
set list↲
set tabstop=2↲
00 hello^@ hello
01 hello␁ hello
02 hello␂ hello
03 hello␃ hello
04 hello␄ hello
05 hello␅ hello
06 hello␆ hello
07 hello␇ hello
08 hello␈ hello
09 hello␉ hello
10 hello
hello
11 hello␋ hello
12 hello␌ hello
13 hello␍ hello
14 hello␎ hello
15 hello␏ hello
16 hello␐ hello
17 hello␑ hello
18 hello␒ hello
19 hello␓ hello
20 hello␔ hello
21 hello␕ hello
22 hello␖ hello
23 hello␗ hello
24 hello␘ hello
25 hello␙ hello
26 hello␚ hello
27 hello␛ hello
28 hello␜ hello
29 hello␝ hello
30 hello␞ hello
31 hello␟ hello
127hello␡ hello
Quite any character can be managed by "consealing" in .vimrc. 10 is not working. 0 is not working from .vimrc but OK from vim command line (vim/vim#8754). You can use any unicode glyphe, I choose the https://en.wikipedia.org/wiki/Control_Pictures
set encoding=utf-8
syntax match Entity "^A" conceal cchar=␁
syntax match Entity "^B" conceal cchar=␂
syntax match Entity "^C" conceal cchar=␃
syntax match Entity "^D" conceal cchar=␄
syntax match Entity "^E" conceal cchar=␅
syntax match Entity "^F" conceal cchar=␆
syntax match Entity "^G" conceal cchar=␇
syntax match Entity "^H" conceal cchar=␈
syntax match Entity " " conceal cchar=␉
syntax match Entity "^K" conceal cchar=␋
syntax match Entity "^L" conceal cchar=␌
syntax match Entity "^M" conceal cchar=␍
syntax match Entity "^N" conceal cchar=␎
syntax match Entity "^O" conceal cchar=␏
syntax match Entity "^P" conceal cchar=␐
syntax match Entity "^Q" conceal cchar=␑
syntax match Entity "^R" conceal cchar=␒
syntax match Entity "^S" conceal cchar=␓
syntax match Entity "^T" conceal cchar=␔
syntax match Entity "^U" conceal cchar=␕
syntax match Entity "^V" conceal cchar=␖
syntax match Entity "^W" conceal cchar=␗
syntax match Entity "^X" conceal cchar=␘
syntax match Entity "^Y" conceal cchar=␙
syntax match Entity "^Z" conceal cchar=␚
syntax match Entity "^[" conceal cchar=␛
syntax match Entity "^\" conceal cchar=␜
syntax match Entity "^]" conceal cchar=␝
syntax match Entity "^^" conceal cchar=␞
syntax match Entity "^_" conceal cchar=␟
syntax match Entity "^?" conceal cchar=␡
set conceallevel=1
set concealcursor=nc
00 hello� hello
01 hello� hello
02 hello� hello
03 hello� hello
04 hello� hello
05 hello� hello
06 hello� hello
07 hello� hello
08 hello� hello
09 hello hello
10 hello
hello
11 hello� hello
12 hello hello
13 hello
hello
14 hello� hello
15 hello� hello
16 hello� hello
17 hello� hello
18 hello� hello
19 hello� hello
20 hello� hello
21 hello� hello
22 hello� hello
23 hello� hello
24 hello� hello
25 hello� hello
26 hello� hello
27 hello� hello
28 hello� hello
29 hello� hello
30 hello� hello
31 hello� hello
127hello� hello
0,9,10,13 are interpreted by firefox (try yourself)..
user@minipc1:~/fred$ less test.txt
"test.txt" may be a binary file. See it anyway?y
00 hello^@ hello
01 hello^A hello
02 hello^B hello
03 hello^C hello
04 hello^D hello
05 hello^E hello
06 hello^F hello
07 hello^G hello
08 hell hello
09 hello hello
10 hello
hello
11 hello^K hello
12 hello^L hello
13 hello^M hello
14 hello^N hello
15 hello^O hello
16 hello^P hello
17 hello^Q hello
18 hello^R hello
19 hello^S hello
20 hello^T hello
21 hello^U hello
22 hello^V hello
23 hello^W hello
24 hello^X hello
25 hello^Y hello
26 hello^Z hello
27 helloESC hello
28 hello^\ hello
29 hello^] hello
30 hello^^ hello
31 hello^_ hello
127hello^? hello
8-10 and 27 are interpreted by less.
user@minipc1:~/fred$ tr "\000-\011,\013-\037,\177" "-" < test.txt
00 hello- hello
01 hello- hello
02 hello- hello
03 hello- hello
04 hello- hello
05 hello- hello
06 hello- hello
07 hello- hello
08 hello- hello
09 hello- hello
10 hello
hello
11 hello- hello
12 hello- hello
13 hello- hello
14 hello- hello
15 hello- hello
16 hello- hello
17 hello- hello
18 hello- hello
19 hello- hello
20 hello- hello
21 hello- hello
22 hello- hello
23 hello- hello
24 hello- hello
25 hello- hello
26 hello- hello
27 hello- hello
28 hello- hello
29 hello- hello
30 hello- hello
31 hello- hello
127hello- hello
All can be catched by tr.