gistfile1.rb

#!/usr/bin/env ruby

special_chars = Hash[%w[<< >>]
  .map{ |c| [c, c.unpack('a1a1')
  .flat_map{ |n| n.unpack('H*') }
  .join('-').upcase]}]
  .merge(Hash[%w[* & + - ! ?]
  .map{|c| [c, c.unpack('H*')[0].upcase]}])

output #=> {"<<"=>"3C-3C", ">>"=>"3E-3E", "*"=>"2A", "&"=>"26", "+"=>"2B", "-"=>"2D", "!"=>"21", "?"=>"3F"}