File: dedent.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 # dedent [options...] [files...]
  27 #
  28 # Ignore the common leading-space indentation from the input(s).
  29 #
  30 # The help option is `-h`, `--h`, `-help`, or `--help`.
  31 
  32 
  33 buffered=0
  34 
  35 case "$1" in
  36     -b|--b|-buffered|--buffered)
  37         buffered=1
  38         shift
  39     ;;
  40 
  41     -h|--h|-help|--help)
  42         awk '/^# +dedent /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  43         exit 0
  44     ;;
  45 esac
  46 
  47 [ "$1" = '--' ] && shift
  48 
  49 # show all non-existing files given
  50 failed=0
  51 for arg in "$@"; do
  52     if [ "${arg}" = "-" ]; then
  53         continue
  54     fi
  55     if [ ! -e "${arg}" ]; then
  56         printf "no file named \"%s\"\n" "${arg}" >&2
  57         failed=1
  58     fi
  59 done
  60 
  61 if [ "${failed}" -gt 0 ]; then
  62     exit 2
  63 fi
  64 
  65 flush=0
  66 if [ "${buffered}" -eq 0 ] && { [ -p /dev/stdout ] || [ -t 1 ]; }; then
  67     flush=1
  68 fi
  69 
  70 awk -v flush="${flush}" '
  71     BEGIN { n = -1 }
  72 
  73     {
  74         if (n == 0) {
  75             print
  76             if (flush) fflush()
  77             next
  78         }
  79 
  80         indent = 0
  81         if (match($0, /^ +/)) indent = RLENGTH
  82 
  83         m = n
  84         if (n > indent || n < 0) n = indent
  85         if (m != 0 && n == 0) {
  86             for (i = 1; i <= NR; i++) print lines[i]
  87             for (i = 1; i <= NR; i++) delete lines[i]
  88             next
  89         }
  90 
  91         lines[NR] = $0
  92     }
  93 
  94     END {
  95         if (n > 0) for (i = 1; i <= NR; i++) print substr(lines[i], n + 1)
  96     }
  97 ' "$@"