re = /(?<=\s|^)\b\d{3}-\d{2}-\d{4}\b(?=\s|$)/m
str = 'John Doe SSN# 123-12-1235
100-123-45-1234-99
John Smith, SSN, 123-45-1234
100-123-45-1234-99
123-45-1234'
# Print the match result
str.scan(re) do |match|
puts match.to_s
end
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