While following another great Ryan Bates Railscast, I had a couple of problems on my Ubuntu 8.04 development machine:

• Rails 2.1.0’s ActionController wants version 0.6.1 or later of the ruby-prof gem, but the usual gem repositories only have 0.6.0 now. I found suggestions to install Jeremy Kemper’s fork on Github, but though I’d added GitHub as a gem source, installing jeremy-ruby-prof didn’t work because that installed his version with that name, which didn’t help ActionController. What worked was:

  sudo gem uninstall jeremy-ruby-prof # be sure to uninstall old attempts!
  git clone git://github.com/jeremy/ruby-prof.git
  cd ruby-prof
  rake gem
  sudo gem install pkg/ruby-prof-0.6.1.gem

• Then, script/performance/request ran, but generated several strange error messages instead of producing results:

  Couldnt get a file descriptor referring to the console
  Could not get a file descriptor referring to the console
  Couldnt get a file descriptor referring to the console
  Could not get a file descriptor referring to the console
  

  This turned out to be because script/performance/request wants to use ‘open’ to open its output files (a text file and an HTML document), but on Ubuntu, /usr/bin/open is a link to /usr/bin/openvt, which didn’t do what we want (and generated those error messages). I’m not sure what else uses ‘open’, but this did the right thing: it lets Firefox open the files:

  sudo ln -sf /usr/bin/firefox /usr/bin/open