re = /ITEM1\.([\s\S]*?)ITEM1A\./m
str = 'ITEM1.BUSINESS (Dollars in thousands) General AAR CORP. and its subsidiaries are referred to herein collectively as "AAR," "Company," ITEM1A.RISK FACTORS The following is a description of some of the principal risks inherent in our business. ITEM1A. some other text ITEM2'
# 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