re = /^NEVPT2.*\n(?:(?!end$).*\n)*end$/m
str = 'JOB 1
CASSCF RESULTS
***
Lots of text
***
end
NEVPT2 RESULTS
***
Lots of text
***
end
JOB 2
CASSCF RESULTS
***
Lots of text
***
end
NEVPT2 RESULTS
***
Lots of text
***
end
………………
JOB 31
CASSCF RESULTS
***
Lots of text
***
end
NEVPT2 RESULTS
***
Lots of text
***
end'
# 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