As root:

cd src/rubygems-1.3.7
export RUBYOPT=""
ruby setup.rb

RUBYOPT is set in .bashrc to include ruby gems, but means that ruby will fail if it can't find a working gems install.

Gems commonly used:

• mini_exiftool (which requires command-line tool exiftool, source package Image-ExifTool-X.XX.tar.gz)
• exifr
• fileutils

gem update --system          # may need to be administrator or root
gem install mini_exiftool

• Qt4 (libraries and SDK, currently 400+MB): http://qt.nokia.com/downloads
• qt4-qtruby: http://rubyforge.org/projects/korundum/

• exiftool
• jhead
• gems listed above