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 #   -f, -fade    use a faded/gray style instead of highlighting
  43 #   -g, -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 #   -tsv         split fields using tabs, same as using -F "\t"
  47 #   -u           underline (relevant) lines instead of highlighting them
  48 
  49 
  50 cmd='awk'
  51 ansi='7m'
  52 buf=0
  53 ins=0
  54 tsv=0
  55 
  56 while [ $# -gt 0 ]; do
  57     case "$1" in
  58         -b|--b|-buffered|--buffered) buf=1; shift; continue ;;
  59 
  60         -F)
  61             [ $# -ge 2 ] && cmd="${cmd} -F $2"; shift 2; continue
  62             printf "expected value after -F option\n" >&2
  63             exit 1
  64         ;;
  65 
  66         -F*) cmd="${cmd} $1"; shift; continue ;;
  67 
  68         -f|--f|-fade|--fade|-faded|--faded)
  69             ansi='38;2;168;168;168m'; shift; continue
  70         ;;
  71 
  72         -g|--g|-gray|--gray) ansi='48;2;216;216;216m'; shift; continue ;;
  73 
  74         -h|--h|-help|--help)
  75             awk '/^# +hawk /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  76             exit 0
  77         ;;
  78 
  79         -i|--i|-ins|--ins|-insensitive|--insensitive) ins=1; shift; continue ;;
  80 
  81         -tsv|--tsv) tsv=1; shift; continue ;;
  82 
  83         -u|--u|-underline|--underline|-underlined|--underlined)
  84             ansi='4m'; shift; continue
  85         ;;
  86 
  87         -v)
  88             [ $# -ge 2 ] && cmd="${cmd} -v $2" && shift 2 && continue
  89             printf "expected variable assignment after -v option\n" >&2
  90             exit 1
  91         ;;
  92 
  93         -) break ;;
  94 
  95         --) shift; break ;;
  96 
  97         -*) printf "%s: unsupported option '%s'\n" "$0" "$1" >&2; exit 1 ;;
  98     esac
  99 
 100     break
 101 done
 102 
 103 cond="${1:-1}"
 104 [ $# -gt 0 ] && shift
 105 
 106 # show all non-existing files given
 107 failed=0
 108 for arg in "$@"; do
 109     [ "${arg}" = "-" ] && continue
 110     [ -e "${arg}" ] && continue
 111     printf "%s: no file named \"%s\"\n" "$0" "${arg}" >&2
 112     failed=1
 113 done
 114 
 115 [ "${failed}" -gt 0 ] && exit 2
 116 
 117 flush=''
 118 if [ "${buf}" -eq 0 ] && { [ -p /dev/stdout ] || [ -t 1 ]; }; then
 119     flush='; fflush()'
 120 fi
 121 
 122 ci='
 123 BEGIN {
 124     if (IGNORECASE == "") {
 125         m = "your `awk` command lacks case-insensitive regex-matching"
 126         print(m) > "/dev/stderr"
 127         exit 125
 128     }
 129     IGNORECASE = 1
 130 }
 131 '
 132 [ "${ins}" -eq 0 ] && ci=''
 133 
 134 src="${ci}"'
 135 {
 136     # keep original record/line to (maybe) emit it later
 137     RECORD = $0
 138 
 139     # ignore cursor-movers and style-changers
 140     gsub(/\x1b\[[0-9;]*[A-Za-z]/, "")
 141     # ignore OSC sequences
 142     gsub(/\x1b\][^\x1b]+\x1b\\/, "")
 143 }
 144 
 145 ('"${cond}"') {
 146     gsub(/\x1b\[0m/, "\x1b[0m\x1b['"${ansi}"'", RECORD)
 147     printf("\x1b['"${ansi}"'%s\x1b[0m%s", RECORD, ORS)'"${flush}"'
 148     next
 149 }
 150 
 151 { printf("%s%s", RECORD, ORS)'"${flush}"' }
 152 '
 153 
 154 if [ "${tsv}" -eq 1 ]; then
 155     ${cmd} -F "\t" "${src}" "$@"
 156 else
 157     ${cmd} "${src}" "$@"
 158 fi