re = /^[^_]+_(.*)_[^_]+$/m
str = 'cito001_LULUXCACN_PZ46_DI_SA_DRITTLAND_20210422074609.csv
cito001_GBCVTBACN_DRITTLAND_033_Di_Fr_20210422051506.csv
adwfwm_NLHAGIACE_Export_028_DI_SA_20210422074803.csv'
# 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