File: stomp.sh
   1 #!/bin/sh
   2 
   3 # The MIT License (MIT)
   4 #
   5 # Copyright © 2020-2025 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 # stomp [filepaths...]
  27 #
  28 #
  29 # Turn runs of empty lines into single empty lines, effectively squeezing
  30 # paragraphs vertically, so to speak; runs of empty lines both at the start
  31 # and at the end are ignored.
  32 #
  33 # This script also ensures no lines across inputs are accidentally joined,
  34 # since all lines it outputs end with line-feeds, even when the original
  35 # files don't.
  36 
  37 
  38 case "$1" in
  39     -h|--h|-help|--help)
  40         # show help message, using the info-comment from this very script
  41         awk '/^# +stomp /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  42         exit 0
  43     ;;
  44 esac
  45 
  46 awk '
  47     /^\r?$/ {
  48         empty = 1
  49         next
  50     }
  51 
  52     empty {
  53         if (n > 0) print ""
  54         empty = 0
  55     }
  56 
  57     {
  58         print; fflush()
  59         n++
  60     }
  61 ' "$@"