Get file creation time

creation_time.rb

# 支持 MacOS, ext4 文件系统的 Linux
# 参考：http://moiseevigor.github.io/software/2015/01/30/get-file-creation-time-on-linux-with-ext4/
#
def creation_time(file_path)
  case RUBY_PLATFORM
  when /bsd/, /darwin/
    return %x{mdls -raw -name kMDItemFSCreationDate #{file_path}}
  when /linux/
    inode = %x{ls -di "#{file_path}" | cut -d ' ' -f 1}.strip
    fs = %x{df "#{file_path}"  | tail -1 | awk '{print $1}'}.strip
    out = %x{sudo debugfs -R 'stat <'"#{inode}"'>' "#{fs}" 2>/dev/null}.strip
    return out.match(/crtime.*--\s*\K.*/)[0]
  end
end

if $0 == __FILE__
  puts creation_time(ARGV.first)
end