File: hawk.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 # hawk [options...] [awk condition...] [files...]
  27 #
  28 #
  29 # Highlight (lines) satisfying an AWK condition/expression, keeping other
  30 # lines the same. When not given a condition, all lines are highlighted.
  31 #
  32 # The handy case-insensitive shortcut options may cause this tool to fail,
  33 # if the main AWK tool installed doesn't support the special IGNORECASE
  34 # variable.
  35 #
  36 # The AWK options available only in single-dash versions are
  37 #
  38 #   -F fs, -Ffs, -F=fs    make `fs` the field separator
  39 #
  40 # The other options are, available both in single and double-dash versions
  41 #
  42 #   -fade        use a faded/gray style instead of highlighting
  43 #   -gray        use a gray-background style instead of highlighting
  44 #   -h, -help    show this help message
  45 #   -i, -ins     match regexes case-insensitively; may fail the `awk` tool
  46 #   -plain       add variable `plain`, which is `$0` without ANSI-styles
  47 #   -tsv         split fields using tabs, same as using -F "\t"
  48 #   -u           underline (relevant) lines instead of highlighting them
  49 
  50 
  51 cmd='awk'
  52 ansi='7m'
  53 buf=0
  54 ins=0
  55 plain_mode=0
  56 tsv=0
  57 
  58 while [ $# -gt 0 ]; do
  59     case "$1" in
  60         -b|--b|-buffered|--buffered) buf=1; shift; continue ;;
  61 
  62         -F)
  63             [ $# -ge 2 ] && cmd="${cmd} -F $2"; shift 2; continue
  64             printf "expected value after -F option\n" >&2
  65             exit 1
  66         ;;
  67 
  68         -F*) cmd="${cmd} $1"; shift; continue ;;
  69 
  70         -fade|--fade|-faded|--faded)
  71             ansi='38;2;168;168;168m'; shift; continue
  72         ;;
  73 
  74         -gray|--gray) ansi='48;2;216;216;216m'; shift; continue ;;
  75 
  76         -h|--h|-help|--help)
  77             awk '/^# +hawk /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  78             exit 0
  79         ;;
  80 
  81         -i|--i|-ins|--ins|-insensitive|--insensitive) ins=1; shift; continue ;;
  82 
  83         -plain|--plain) plain_mode=1; shift; continue ;;
  84 
  85         -tsv|--tsv) tsv=1; shift; continue ;;
  86 
  87         -u|--u|-underline|--underline|-underlined|--underlined)
  88             ansi='4m'; shift; continue
  89         ;;
  90 
  91         -v)
  92             [ $# -ge 2 ] && cmd="${cmd} -v $2" && shift 2 && continue
  93             printf "expected variable assignment after -v option\n" >&2
  94             exit 1
  95         ;;
  96 
  97         -) break ;;
  98 
  99         --) shift; break ;;
 100 
 101         -*) printf "unsupported option '%s'\n" "$1" >&2; exit 1 ;;
 102     esac
 103 
 104     break
 105 done
 106 
 107 cond="${1:-1}"
 108 [ $# -gt 0 ] && shift
 109 
 110 # show all non-existing files given
 111 failed=0
 112 for arg in "$@"; do
 113     [ "${arg}" = "-" ] && continue
 114     [ -e "${arg}" ] && continue
 115     printf "no file named \"%s\"\n" "${arg}" >&2
 116     failed=1
 117 done
 118 
 119 [ "${failed}" -gt 0 ] && exit 2
 120 
 121 flush=''
 122 if [ "${buf}" -eq 0 ] && { [ -p /dev/stdout ] || [ -t 1 ]; }; then
 123     flush='fflush()'
 124 fi
 125 
 126 ci='
 127     BEGIN {
 128         if (IGNORECASE == "") {
 129             m = "your `awk` command lacks case-insensitive regex-matching"
 130             print(m) > "/dev/stderr"
 131             exit 125
 132         }
 133         IGNORECASE = 1
 134     }
 135 '
 136 [ "${ins}" -eq 0 ] && ci=''
 137 
 138 plain='
 139     {
 140         plain = $0
 141         # ignore cursor-movers and style-changers
 142         gsub(/\x1b\[[0-9;]*[A-Za-z]/, "", plain)
 143         # ignore OSC sequences
 144         gsub(/\x1b\][^\x1b]+\x1b\\/, "", plain)
 145     }
 146 '
 147 [ "${plain_mode}" -eq 0 ] && plain=''
 148 
 149 src="${ci}"'
 150 
 151 '"${plain}"'
 152 
 153     ('"${cond}"') {
 154         gsub(/\x1b\[0m/, "\x1b[0m\x1b['"${ansi}"'")
 155         printf("\x1b['"${ansi}"'%s\x1b[0m\n", $0); '"${flush}"'
 156         next
 157     }
 158 
 159     { print; '"${flush}"' }
 160 '
 161 
 162 if [ "${tsv}" -eq 1 ]; then
 163     ${cmd} -F "\t" "${src}" "$@"
 164 else
 165     ${cmd} "${src}" "$@"
 166 fi