File: squeeze.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 # squeeze [options...] [files...]
  27 #
  28 # Aggressively trim unneeded whitespace out of lines, also ignoring leading
  29 # UTF-8 BOMs, and trailing carriage-returns on all lines.
  30 #
  31 # This script also ensures no lines across inputs are accidentally joined,
  32 # since all lines it outputs end with line-feeds, even when the original files
  33 # don't.
  34 #
  35 # The options are, available both in single and double-dash versions
  36 #
  37 #   -h, -help    show this help message
  38 
  39 
  40 buffered=0
  41 
  42 case "$1" in
  43     -b|--b|-buffered|--buffered)
  44         buffered=1
  45         shift
  46     ;;
  47 
  48     -h|--h|-help|--help)
  49         awk '/^# +squeeze /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  50         exit 0
  51     ;;
  52 
  53     -) ;;
  54 
  55     --) shift ;;
  56 
  57     -*)
  58         printf "unsupported option '%s'\n" "$1" >&2
  59         exit 1
  60     ;;
  61 esac
  62 
  63 # show all non-existing files given
  64 failed=0
  65 for arg in "$@"; do
  66     [ "${arg}" = "-" ] && continue
  67     [ -e "${arg}" ] && continue
  68     printf "no file named \"%s\"\n" "${arg}" >&2
  69     failed=1
  70 done
  71 
  72 [ "${failed}" -gt 0 ] && exit 2
  73 
  74 flush=0
  75 if [ "${buffered}" -eq 0 ] && { [ -p /dev/stdout ] || [ -t 1 ]; }; then
  76     flush=1
  77 fi
  78 
  79 awk -v flush="${flush}" '
  80     # ignore leading UTF-8 BOMs on the first line of each input, when present
  81     FNR == 1 { gsub(/^\xef\xbb\xbf/, "") }
  82 
  83     {
  84         # ignore leading spaces, trailing spaces and/or carriage-returns
  85         gsub(/^ +| *\r?$/, "")
  86         # ignore spaces around tabs
  87         gsub(/ *\t */, "\t")
  88         # turn all runs of multiple spaces into single spaces
  89         gsub(/  +/, " ")
  90 
  91         print
  92         if (flush) fflush()
  93     }
  94 ' "$@"