re = /^(?=.{5,12}$)(?=(?:[^a-zA-Z\u0590-\u05fe\n]*[a-zA-Z\u0590-\u05fe]){4}[^a-zA-Z\u0590-\u05fe\n]*$)[a-zA-Z\u0590-\u05fe]{0,4}[0-9]{3,8}[a-zA-Z\u0590-\u05fe]{0,4}$/m
str = 'abcd123efgh
abc123efgh
abc123efg
ab123efg
ab123ef
a123ef
a123e
ab123c
abc123d
123abcd
123e
123e'
# 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