File: junk.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 # junk [options...] [byte-count...]
  27 #
  28 # Emit the given count of random/junk bytes, or 1024 random bytes by default.
  29 #
  30 # The options are, available both in single and double-dash versions
  31 #
  32 #   -h, -help    show this help message
  33 
  34 
  35 case "$1" in
  36     -h|--h|-help|--help)
  37         awk '/^# +junk /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  38         exit 0
  39     ;;
  40 esac
  41 
  42 n='1024'
  43 # detect a leading number, and use it as a byte-count value
  44 if echo "$1" | grep -q -E '^[+-]?[0-9]+$'; then
  45     n="$1"
  46     shift
  47 fi
  48 
  49 [ "$1" = '--' ] && shift
  50 
  51 head -c "${n}" /dev/urandom