path

#!/usr/bin/env ruby -w

# Present and manipulate paths.

require 'optparse'

class Path
  def initialize(var_name, *args)
    path_string = args.empty? ? ENV[var_name] : args.join(":")
    @elements = path_string.split(/:/)
  end

  def clean
    @elements.delete('')
    @elements.uniq!
  end

  def show(separator)
    puts @elements.join(separator)
  end
end


def parse_args
  options = {
    var_name: 'PATH'
  }

  op = OptionParser.new do |opts|
    opts.banner = <<-EOS.gsub(/^ */, '')
      Usage: #{opts.program_name} [option]... [argument]...

      If called with non-flag command-line arguments, assemble them into a
      new PATH value and emit it. The current $PATH is not included unless
      explicitly mentioned: this lets you control the prepending or
      appending of new values.

      In the absence of non-flag command-line arguments, emit the current
      $PATH.
    EOS

    opts.on("-c", "--clean", "Clean path, removing any dupes.") do
      options[:clean] = true
    end

    opts.on("-m", "--manpath", "Examine MANPATH rather than PATH.") do
      options[:var_name] = 'MANPATH'
    end

    opts.on("-p", "--pack", "Pack path into one long line.") do
      options[:pack] = true
    end
  end

  args = op.parse!

  [args, options]
end

# ------------------

args, options = parse_args

separator = options[:pack] ? ":" : "\n"

path = Path.new(options[:var_name], *args)
path.clean if options[:clean]
path.show(separator)