re = /^6(?!011)(?:0[0-9]{14}|52[12][0-9]{12})$/m
str = '6012345678901234
6521123456789012
6522123456789012
60123456789012341
65211234567890122
65221234567890123
6011221234567890
6522123456789012
'
# 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