a bioruby code for http://twitter.com/motthy/status/413701761468084224

a.rb

# Split a multi fasta file into single fasta files (1.fasta, 2.fasta, ...)
# > ruby a.rb multi.fasta

require 'rubygems'
gem 'bio'

Bio::FlatFile.auto($<).each_with_index do |entry, i|
  File.open("#{i+1}.fasta", "w") do |f|
    f.puts entry.to_s
  end
end