re = /^(\S+) (?=(?s:.)*(\1.*)).*/m
str = 'user1 jul/12/12
user5 jul/13/13
user1 jul/14/12
user1 jul/12/12
user5 jul/13/13
user1 jul/14/12
user3 jan/12/12
user1 jul/12/12
user5 jul/13/13
user1 jul/14/12
user1 jul/12/12
user5 jul/13/13
user1 jul/14/12
user1 jul/12/12
user6 aug/06/06
user5 jul/13/13
user1 jul/14/12
user1 jul/12/12
user5 jul/13/13
user1 jul/14/12
user1 aug/12/12
user5 feb/13/13
user1 dec/14/12
user1 jul/12/12
user5 jul/13/13
user1 jul/14/12
user2 jun/15/14'
# 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