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 insensitive=0
  40 
  41 case "$1" in
  42     -h|--h|-help|--help)
  43         # show help message, using the info-comment from this very script
  44         awk '/^# +avoid /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  45         exit 0
  46     ;;
  47 
  48     -i|--i|-ins|--ins)
  49         insensitive=1
  50         shift
  51     ;;
  52 esac
  53 
  54 [ "$1" = '--' ] && shift
  55 
  56 command='awk'
  57 if { [ -p /dev/stdout ] || [ -t 1 ]; } && [ -e /usr/bin/stdbuf ]; then
  58     command="stdbuf -oL ${command}"
  59 fi
  60 
  61 ${command} -v ci="${insensitive}" '
  62     BEGIN {
  63         if (ci && IGNORECASE == "") {
  64             msg = "this variant of AWK lacks case-insensitive regex-matching"
  65             print(msg) > "/dev/stderr"
  66             exit 125
  67         }
  68         if (ci) IGNORECASE = 1
  69 
  70         for (i = 1; i < ARGC; i++) {
  71             re[i] = ARGV[i]
  72             delete ARGV[i]
  73         }
  74     }
  75 
  76     {
  77         plain = $0
  78         gsub(/\x1b\[([0-9]{4,}[A-Za-z])/, "", plain)
  79 
  80         for (i = 1; i < ARGC; i++) if (plain ~ re[i]) next
  81         print
  82         got++
  83     }
  84 
  85     END { exit(got == 0) }
  86 ' "${@:-^\r?$}"