re = /.*?LU2w26227 (.*?) Belob.*/m
str = 'ABC This is an example Vores ref.: 23244-2234 LW782837673 LU2w26227 Ole Hansen s.r.t Belob to: sajsad'
subst = '$1'
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
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