re = /(?=\{Infobox)(\{([^{}]|(?1))*\})/m
str = '{{Infobox xyz
|aaa= Xyz
|bbb= [[Xyz]]
|ccc=[[File:xyz.jpg|thumb|Xyz.]]
|ddd= {{lang|en|xyz}}
}}
[[File:abc.jpg|thumb|Abc.]]'
# 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