show the contents of multiple files with file names

showfile

#!/bin/bash
set -eu
: ${FILENAME_COLOR:="\e[35m"}
if [ -t 1 ]; then
    color=$FILENAME_COLOR
else
    color=
fi

for opt in "$@"; do
    case "$opt" in
        --color)
            color=$FILENAME_COLOR
            shift
            ;;
        --color=*)
            coloropt="${opt#--color=}"
            case "$coloropt" in
                yes | true)
                    color="$FILENAME_COLOR"
                    ;;
                no | none | false)
                    color=""
                    ;;
                *)
                    echo "wrong option for color" 1>&2
                    exit 1
                    ;;
            esac
            shift
            ;;
        --)
            param+=("$@")
            break
            ;;
        *)
            param+=("$1")
            shift
            ;;
    esac
done

set -- "${param[@]}"

while [ "$#" -gt 0 ]; do
    if [ ! -e "$1" ]; then
        echo "$1: no such file or directory" 1>&2
        exit 1
    fi
    printf "$color$1:\e[m\n"
    cat "$1"
    shift
    [ "$#" -gt 0 ] && echo
done

showfile2

#!/usr/bin/env ruby
# ruby版。ライブラリのおかげでbash版よりかなり短く書ける
require 'optparse'

FILENAME_COLOR = (ENV["FILENAME_COLOR"] || "\e[35m").sub(/\\e/, "\e")
color = $stdout.tty? ? FILENAME_COLOR : ""
parser = OptionParser.new
parser.on("--color [VAL]", TrueClass) {|col| color = col ? FILENAME_COLOR : ""}
parser.parse!(ARGV)

last_index = ARGV.size - 1
ARGV.each_with_index do |file, index|
  unless File.exists?(file)
    $stderr.puts "#{file}: no such file or directory"
    exit 1
  end
  puts "#{color}#{file}:\e[m"
  print File.read(file)
  puts if index < last_index
end