re = /^(?:You're assigned to kill|You have received a new Slayer assignment from .*:) (.*?)(?: in the Wilderness)?(?:; only | \()(\d*)(?: more to go\.|\))$/m
str = 'You\'re assigned to kill Dust Devils; only 123 more to go.
You\'re assigned to kill Suqahs in the Wilderness; only 211 more to go.
You have received a new Slayer assignment from breaklulz: Dust Devils (377)'
# 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