File: avoid.sh
   1 #!/bin/sh
   2 
   3 # The MIT License (MIT)
   4 #
   5 # Copyright © 2025 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 # avoid [options...] [regular expressions...]
  27 #
  28 # Avoid/ignore lines which match any of the extended-mode regular expressions
  29 # given. When not given any regex, ignore all empty lines by default.
  30 #
  31 # The options are, available both in single and double-dash versions
  32 #
  33 #   -h       show this help message
  34 #   -help    show this help message
  35 #
  36 #   -i       match regexes case-insensitively
  37 #   -ins     match regexes case-insensitively
  38 
  39 
  40 case "$1" in
  41     -h|--h|-help|--help)
  42         # show help message, using the info-comment from this very script
  43         awk '/^# +avoid /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  44         exit 0
  45     ;;
  46 esac
  47 
  48 insensitive=0
  49 case "$1" in
  50     -i|--i|-ins|--ins)
  51         insensitive=1
  52         shift
  53     ;;
  54 esac
  55 
  56 [ "$1" = '--' ] && shift
  57 
  58 command='awk'
  59 if [ -e /usr/bin/gawk ]; then
  60     command='/usr/bin/gawk'
  61 fi
  62 if [ -p /dev/stdout ] || [ -t 1 ]; then
  63     command="stdbuf -oL ${command}"
  64 fi
  65 
  66 ${command} -v ci="${insensitive}" '
  67     BEGIN {
  68         if (ci && IGNORECASE == "") {
  69             msg = "this variant of AWK lacks case-insensitive regex-matching"
  70             print(msg) > "/dev/stderr"
  71             exit 125
  72         }
  73         if (ci) IGNORECASE = 1
  74 
  75         for (i = 1; i < ARGC; i++) {
  76             re[i] = ARGV[i]
  77             delete ARGV[i]
  78         }
  79     }
  80 
  81     {
  82         for (i = 1; i < ARGC; i++) if ($0 ~ re[i]) next
  83         print
  84         got++
  85     }
  86 
  87     END { exit(got == 0) }
  88 ' "${@:-^\r?$}"