If you want to access the modification time of a file on a remote server via Net::SFTP, use the following:

Net::SFTP.start('sftp.foo.com', 'user', :password => 'pass') do |sftp|
  sftp.dir.glob('/remote/path', '**/*.rb') do |file|
    puts file.attributes.mtime
  end
end

You can also get these attributes as well:

• permissions
• uid
• gid
• size
• atime (time of last access)

mtime and atime return the time in number of seconds so pass this into Time.at to convert it to a Time object.

(Source: stackoverflow.com)