re = /total\s+amount\s*(?::\s*)?\d[\d,.]*+(?!\s*kgs)/mi
str = 'task1. total amount 5,887.99 kgs
task2. total amount 5,887.99kgs
task3. total amount 5,887.99 usd
task4. total amount 5,887.99usd'
# 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