Re: bug#47281: sed: problem with hex replace a literal '$'

[Bastian Bittorf]

On Sun, Mar 21, 2021 at 07:21:43PM +0100, Nora Platiel wrote:
> > Sent: Sunday, March 21, 2021 at 3:53 PM
> >

see:
https://lists.gnu.org/archive/html/bug-sed/2021-03/msg00000.html

> >
> > I understand, that this behaviour is valid and not a bug.

[...]

> > Indeed this is really awkward, but I have to
> > accept that and use now something like that:
> 
> I understand the inconvenience.
> 
> > # case "$hex" in
> > #   24|2a|2e|5b|5c|5d|5e)
> 
> Please note that those characters need to be escaped for the *regexp* part.
> For the *replacement* part of an "s" command you need to escape \ and &
> It is safe to just add & (\x26) to your list and use it for both the regexp 
> part and the replacement part, but you cannot just escape everything because 
> many characters become special when escaped.
>

Thanks again Nora for your helpful answer.

Attached is a small script for checking the correctness:
It seems, there is no need to esacpe '&' in hexmode, but
i'am not able to replace symbols from 0x00 to 0x0a (newline),
and this is also somehow clear, because of the line-oriented
inner workings of sed.

Thanks for help,
bye, Bastian

# generated file with all values from 00 to ff:
# 00000000  00 01 02 03 04 05 06 07  08 09 0a 0b 0c 0d 0e 0f  |................|
# 00000010  10 11 12 13 14 15 16 17  18 19 1a 1b 1c 1d 1e 1f  |................|
# 00000020  20 21 22 23 24 25 26 27  28 29 2a 2b 2c 2d 2e 2f  | !"#$%&'()*+,-./|
# 00000030  30 31 32 33 34 35 36 37  38 39 3a 3b 3c 3d 3e 3f  |0123456789:;<=>?|
# 00000040  40 41 42 43 44 45 46 47  48 49 4a 4b 4c 4d 4e 4f  |@ABCDEFGHIJKLMNO|
# 00000050  50 51 52 53 54 55 56 57  58 59 5a 5b 5c 5d 5e 5f  |PQRSTUVWXYZ[\]^_|
# 00000060  60 61 62 63 64 65 66 67  68 69 6a 6b 6c 6d 6e 6f  |`abcdefghijklmno|
# 00000070  70 71 72 73 74 75 76 77  78 79 7a 7b 7c 7d 7e 7f  |pqrstuvwxyz{|}~.|
# 00000080  80 81 82 83 84 85 86 87  88 89 8a 8b 8c 8d 8e 8f  |................|
# 00000090  90 91 92 93 94 95 96 97  98 99 9a 9b 9c 9d 9e 9f  |................|
# 000000a0  a0 a1 a2 a3 a4 a5 a6 a7  a8 a9 aa ab ac ad ae af  |................|
# 000000b0  b0 b1 b2 b3 b4 b5 b6 b7  b8 b9 ba bb bc bd be bf  |................|
# 000000c0  c0 c1 c2 c3 c4 c5 c6 c7  c8 c9 ca cb cc cd ce cf  |................|
# 000000d0  d0 d1 d2 d3 d4 d5 d6 d7  d8 d9 da db dc dd de df  |................|
# 000000e0  e0 e1 e2 e3 e4 e5 e6 e7  e8 e9 ea eb ec ed ee ef  |................|
# 000000f0  f0 f1 f2 f3 f4 f5 f6 f7  f8 f9 fa fb fc fd fe ff  |................|
#
# replacement using all values+1, starting at 0x0b:
# 00000000  00 01 02 03 04 05 06 07  08 09 0a 0c 0d 0e 0f 10  |................|
# 00000010  11 12 13 14 15 16 17 18  19 1a 1b 1c 1d 1e 1f 20  |............... |
# 00000020  21 22 23 24 25 26 27 28  29 2a 2b 2c 2d 2e 2f 30  |!"#$%&'()*+,-./0|
# 00000030  31 32 33 34 35 36 37 38  39 3a 3b 3c 3d 3e 3f 40  |123456789:;<=>?@|
# 00000040  41 42 43 44 45 46 47 48  49 4a 4b 4c 4d 4e 4f 50  |ABCDEFGHIJKLMNOP|
# 00000050  51 52 53 54 55 56 57 58  59 5a 5b 5c 5d 5e 5f 60  |QRSTUVWXYZ[\]^_`|
# 00000060  61 62 63 64 65 66 67 68  69 6a 6b 6c 6d 6e 6f 70  |abcdefghijklmnop|
# 00000070  71 72 73 74 75 76 77 78  79 7a 7b 7c 7d 7e 7f 80  |qrstuvwxyz{|}~..|
# 00000080  81 82 83 84 85 86 87 88  89 8a 8b 8c 8d 8e 8f 90  |................|
# 00000090  91 92 93 94 95 96 97 98  99 9a 9b 9c 9d 9e 9f a0  |................|
# 000000a0  a1 a2 a3 a4 a5 a6 a7 a8  a9 aa ab ac ad ae af b0  |................|
# 000000b0  b1 b2 b3 b4 b5 b6 b7 b8  b9 ba bb bc bd be bf c0  |................|
# 000000c0  c1 c2 c3 c4 c5 c6 c7 c8  c9 ca cb cc cd ce cf d0  |................|
# 000000d0  d1 d2 d3 d4 d5 d6 d7 d8  d9 da db dc dd de df e0  |................|
# 000000e0  e1 e2 e3 e4 e5 e6 e7 e8  e9 ea eb ec ed ee ef f0  |................|
# 000000f0  f1 f2 f3 f4 f5 f6 f7 f8  f9 fa fb fc fd fe ff 00  |................|

sed-test-hex.sh
Description: Bourne shell script