#!/bin/sh

# The MIT License (MIT)
#
# Copyright © 2020-2025 pacman64
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the “Software”), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.


# catl [options...] [filepaths...]
#
# Unlike `cat`, conCATenate Lines ignores leading UTF-8 BOMs, trailing
# carriage-returns on all lines, and ensures no lines across inputs are
# accidentally joined, since all lines it outputs end with line-feeds,
# even when the original files don't.
#
# The only option available is to show this help message, using any of
# `-h`, `--h`, `-help`, or `--help`, without the quotes.


# handle help options
case "$1" in
    -h|--h|-help|--help)
        awk '/^# +catl /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
        exit 0
    ;;
esac

awk '
    # ignore leading UTF-8 BOMs on the first line of each input, when present
    FNR == 1 { gsub(/^\xef\xbb\xbf/, "") }

    # ignore trailing carriage-returns before emitting lines; keep flushing
    # output-buffer for each line, in case input lines coming `stuttering`
    { gsub(/\r$/, ""); print; fflush() }
' "$@"