re = /^(?!.{81})(?:\w+[.-])*\w{1,50}@\w{1,25}(?:[.-]\w+)*\.\w{2,3}$/m
str = 'test@test.com
12345678901234567890123456789012345678901234567890@1234567890123456789012345.com
test.test.test@1234567890123456789012345.com
test.test.test@12345678901234567890123456.com'
# 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