File: pawk.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 # pawk [options...] [awk expression...] [files...]
  27 #
  28 # Print AWK expression for each input line: this is a convenient shortcut
  29 # to type less when using AWK to transform all input lines/records.
  30 #
  31 # When not given an expression, the default is to use whole lines/records.
  32 # A `.` (no quotes) for the expression also enables the default behavior.
  33 #
  34 # The options are, available both in single and double-dash versions
  35 #
  36 #   -h, -help    show this help message
  37 #   -i, -ins     match regexes case-insensitively; may fail `awk`
  38 #   -tsv         tab-separated values: split input fields using tabs
  39 
  40 
  41 case "$1" in
  42     -h|--h|-help|--help)
  43         awk '/^# +pawk /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  44         exit 0
  45     ;;
  46 esac
  47 
  48 tsv=0
  49 buf=0
  50 ins=0
  51 cmd='awk'
  52 
  53 while [ $# -gt 0 ]; do
  54     case "$1" in
  55         -b|--b|-buffered|--buffered) buf=1; shift; continue ;;
  56 
  57         -F)
  58             if [ $# -lt 2 ]; then
  59                 printf "%s: expected value after -F option\n" "$0" >&2
  60                 exit 1
  61             fi
  62             cmd="${cmd} -F $2"; shift 2; continue
  63         ;;
  64 
  65         -F*) cmd="${cmd} $1"; shift; continue ;;
  66 
  67         -v)
  68             if [ $# -lt 2 ]; then
  69                 printf "%s: missing variable assignment after -v option\n" \
  70                     "$0" >&2
  71                 exit 1
  72             fi
  73             cmd="${cmd} -v $2"; shift 2; continue
  74         ;;
  75 
  76         -i|--i|-ins|--ins|-insensitive|--insensitive) ins=1; shift; continue ;;
  77 
  78         -tsv|--tsv) tsv=1; shift; continue ;;
  79 
  80         -) break ;;
  81 
  82         --) shift; break ;;
  83 
  84         -*)
  85             printf "%s: unsupported option %s\n" "$0" "$1" >&2
  86             exit 1
  87         ;;
  88     esac
  89 
  90     break
  91 done
  92 
  93 expr="${1:-\$0}"
  94 [ $# -gt 0 ] && shift
  95 if [ "${expr}" = '.' ]; then
  96     expr='$0'
  97 fi
  98 
  99 # show all non-existing files given
 100 failed=0
 101 for a in "$@"; do
 102     [ "$a" = '-' ] && continue
 103     [ -e "$a" ] && continue
 104     printf "%s: no file named \"%s\"\n" "$0" "$a" >&2
 105     failed=1
 106 done
 107 
 108 [ "${failed}" -gt 0 ] && exit 2
 109 
 110 ci='
 111     BEGIN {
 112         if (IGNORECASE == "") {
 113             m = "your `awk` command lacks case-insensitive regex-matching"
 114             print(m) > "/dev/stderr"
 115             exit 125
 116         }
 117         IGNORECASE = 1
 118     }
 119 '
 120 if [ "${ins}" -eq 0 ]; then
 121     ci=''
 122 fi
 123 
 124 flush=''
 125 if [ "${buf}" -eq 0 ] && { [ -p /dev/stdout ] || [ -t 1 ]; }; then
 126     flush='; fflush()'
 127 fi
 128 
 129 src="${ci}"'
 130     { print ('"${expr}"')'"${flush}"' }
 131 '
 132 
 133 if [ "${tsv}" -eq 1 ]; then
 134     ${cmd} -F "\t" -v OFS="\t" "${src}" "$@"
 135 else
 136     ${cmd} "${src}" "$@"
 137 fi