re = /\s+\[.*?(?=\S+$)/m
str = '15-16-00-014716 AND15- [ ] (5) Description of 16-00-014715
15-16-00-014716 AND15- [ ] (5) Description of 1600014715'
subst = ''
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