re = /\[front\](?<front>(?:(?!\[back\])(?!={3,}\s*)(.|\n))*)\[back\](?<back>(?:(?!\[front\])(?!={3,}\s*)(.|\n))*)(?:={3,}\s*|\z)|\[back\](?<back2>(?:(?!\[front\])(?!={3,}\s*)(.|\n))*)\[front\](?<front2>(?:(?!\[back\])(?!={3,}\s*)(.|\n))*)(?:={3,}\s*|\z)/m
str = '===========
[front]
sdfjkhsgdf
sdkljfhgsdofgsd
[back]
sdkfjysgdfisd
(sdf)[sdfsdf]
[dsfsf]
=============
[back]
dddddddddddd
[front]
kikikiki'
# 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