daburi.rb

#!/usr/bin/ruby

require 'shellwords'

HASHFILE = 'sha512'
BASEPATH = 'realfiles'
REFFILE = 'reffile.ref'

alllist = {}
File.open(HASHFILE) do |file|
    file.readlines.each do |line|
        m = line.match(/^([0-9a-f]+)  (.+)$/)
        exit(-1) unless m
        
        hash = m[1]
        filename = File.join(BASEPATH, m[2])
        
        alllist[hash] = (alllist[hash] || []) << filename
    end
end

alllist.each_pair do |k, v|
    next unless v.size > 1
    
    srcfile = v[0]
    v.drop(1).each do |file|
        puts file
        shell = Shellwords.shelljoin(['touch', '-r', file, REFFILE])
        `#{shell}`
        shell = Shellwords.shelljoin(['cp', '--reflink=always', srcfile, file])
        `#{shell}`
        shell = Shellwords.shelljoin(['touch', '-r', REFFILE, file])
        `#{shell}`
    end
end