File: catl.sh
   1 #!/bin/sh
   2 
   3 # The MIT License (MIT)
   4 #
   5 # Copyright © 2024 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 # catl [options...] [filepaths...]
  27 #
  28 # Unlike `cat`, conCATenate Lines ignores leading UTF-8 BOMs, trailing
  29 # carriage-returns on all lines, and ensures no lines across inputs are
  30 # accidentally joined, since all lines it outputs end with line-feeds,
  31 # even when the original files don't.
  32 #
  33 # The only option available is to show this help message, using any of
  34 # `-h`, `--h`, `-help`, or `--help`, without the quotes.
  35 
  36 
  37 # handle help options
  38 case "$1" in
  39     -h|--h|-help|--help)
  40         awk '/^# +catl/, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  41         exit 0
  42     ;;
  43 esac
  44 
  45 awk '
  46     # ignore leading UTF-8 BOMs on the first line of each input, when present
  47     FNR == 1 { gsub(/^\xef\xbb\xbf/, "") }
  48 
  49     # ignore trailing carriage-returns before emitting lines; keep flushing
  50     # output-buffer for each line, in case input lines coming `stuttering`
  51     { gsub(/\r$/, ""); print; fflush() }
  52 ' "$@"