Is it permissible to file nails?

If the purpose of filing nails is to trim them so they do not become long and accumulate dirt underneath, then this is from the Sunnah; according to the Prophet, peace and blessings be upon him: "Five are from the fitra: circumcision, removing pubic hair, trimming the mustache, clipping the nails, and plucking the armpit hair." However, if the intention of filing them is to keep them long for beautification, then this is contrary to the Sunnah.