File: bytedump.sh
   1 #!/bin/sh
   2 
   3 # The MIT License (MIT)
   4 #
   5 # Copyright (c) 2026 pacman64
   6 #
   7 # Permission is hereby granted, free of charge, to any person obtaining a copy
   8 # of this software and associated documentation files (the "Software"), to deal
   9 # in the Software without restriction, including without limitation the rights
  10 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11 # copies of the Software, and to permit persons to whom the Software is
  12 # furnished to do so, subject to the following conditions:
  13 #
  14 # The above copyright notice and this permission notice shall be included in
  15 # all copies or substantial portions of the Software.
  16 #
  17 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23 # SOFTWARE.
  24 
  25 
  26 # bytedump [options...] [files...]
  27 #
  28 # Show bytes in hexadecimal notation, with an ASCII panel on the side which
  29 # shows 2 lines worth of visible-ASCII symbols, which allows reliable matching
  30 # for strings up to 16 symbols long.
  31 #
  32 # The only option available is to show this help message, using any of
  33 # `-h`, `--h`, `-help`, or `--help`, without the quotes.
  34 
  35 
  36 case "$1" in
  37     -h|--h|-help|--help)
  38         awk '/^# +bytedump /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  39         exit 0
  40     ;;
  41 esac
  42 
  43 [ "$1" = '--' ] && shift
  44 
  45 # show all non-existing files given
  46 failed=0
  47 for arg in "$@"; do
  48     if [ "${arg}" = "-" ]; then
  49         continue
  50     fi
  51     if [ ! -e "${arg}" ]; then
  52         printf "no file named \"%s\"\n" "${arg}" >&2
  53         failed=1
  54     fi
  55 done
  56 
  57 if [ "${failed}" -gt 0 ]; then
  58     exit 2
  59 fi
  60 
  61 flush=0
  62 if [ -p /dev/stdout ] || [ -t 1 ]; then
  63     flush=1
  64 fi
  65 
  66 od -v -t x1 "${@:-/dev/stdin}" | awk -v flush="${flush}" '
  67     BEGIN {
  68         s = s "                                "
  69         s = s " !\"#$%&'"'"'()*+,-./0123456789:;<=>?"
  70         s = s "@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_"
  71         s = s "`abcdefghijklmnopqrstuvwxyz{|}~ "
  72         s = s "                                "
  73         s = s "                                "
  74         s = s "                                "
  75         s = s "                                "
  76         split(s, v, "")
  77         for (i = 0; i < 256; i++) vascii[sprintf("%02x", i)] = v[i + 1]
  78     }
  79 
  80     NR > 1 {
  81         printf "%s ", offset
  82 
  83         for (i = 1; i <= n; i++) printf " %s", cur[i]
  84         # printf "%*s", 3 * (maxw - n), "" # not working with busybox
  85         for (i = n + 1; i <= maxw; i++) printf "   "
  86 
  87         printf "  "
  88         for (i = 1; i <= n; i++) printf "%s", vascii[cur[i]]
  89         for (i = 2; i <= NF; i++) printf "%s", vascii[$i]
  90         print ""
  91         if (flush) fflush()
  92     }
  93 
  94     {
  95         n = 0
  96         offset = $1
  97         for (i = 2; i <= NF; i++) cur[++n] = $i
  98         if (maxw < n) maxw = n
  99     }
 100 '