re = /^(?:(?:(?:Miss|Mr|Lady|Mrs|Ms|Dr|Sir)\b|Mr\.)\s+)?(\S+)/m
str = 'Mrs Daksha Karsan
Mr Shane Kyle Taylor
Mr Ahmed Demerdash Keyani
Perry Joe Wilson
Miss Chantelle Reece
Mike Stewart
Dr Ariel Verun Patel
Mr John Sim
'
subst = '$1'
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html