su

# File lib/webrick/utils.rb, line 37
    def su(user)
      if defined?(Etc)
        pw = Etc.getpwnam(user)
        Process::initgroups(user, pw.gid)
        Process::Sys::setgid(pw.gid)
        Process::Sys::setuid(pw.uid)
      else
        warn("WEBrick::Utils::su doesn't work on this platform")
      end
    end