File: avoid.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 # 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, all empty lines are ignored by default.
  30 #
  31 # Input lines always come from the standard input.
  32 #
  33 # The options are, available both in single and double-dash versions
  34 #
  35 #   -h, -help    show this help message
  36 #   -i, -ins     match regexes case-insensitively
  37 
  38 
  39 buffered=0
  40 insensitive=0
  41 
  42 while [ $# -gt 0 ]; do
  43     case "$1" in
  44         -b|--b|-buffered|--buffered)
  45             buffered=1
  46             shift
  47             continue
  48         ;;
  49 
  50         -h|--h|-help|--help)
  51                 awk '/^# +avoid /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  52             exit 0
  53         ;;
  54 
  55         -i|--i|-ins|--ins|-insensitive|--insensitive)
  56             insensitive=1
  57             shift
  58             continue
  59         ;;
  60     esac
  61 
  62     break
  63 done
  64 
  65 [ "$1" = '--' ] && shift
  66 
  67 flush=0
  68 if [ "${buffered}" -eq 0 ] && { [ -p /dev/stdout ] || [ -t 1 ]; }; then
  69     flush=1
  70 fi
  71 
  72 awk -v flush="${flush}" -v ci="${insensitive}" '
  73     BEGIN {
  74         if (ci && IGNORECASE == "") {
  75             msg = "this variant of AWK lacks case-insensitive regex-matching"
  76             print(msg) > "/dev/stderr"
  77             exit 125
  78         }
  79         if (ci) IGNORECASE = 1
  80 
  81         for (i = 1; i < ARGC; i++) {
  82             re[i] = ARGV[i]
  83             delete ARGV[i]
  84         }
  85     }
  86 
  87     {
  88         plain = $0
  89         gsub(/\x1b\[([0-9]{4,}[A-Za-z])/, "", plain)
  90 
  91         for (i = 1; i < ARGC; i++) if (plain ~ re[i]) next
  92         print
  93         if (flush) fflush()
  94         got++
  95     }
  96 
  97     END { exit(got == 0) }
  98 ' "${@:-^\r?$}"