Text comparison: spot the differences I would like to know what would be the best approach to compare two texts and see the differences between them.

For example: 

Sent_1=“This toolset is a set of macros for performing a number of modelling tasks.”

Sent_2=“This tool is a set of macros which help performing a certain number of tasks.”


I do not mind the context/meaning at the moment, but I would like to know what it would be the best approach to spot differences (looking at each word, antecedent and subsequent to it) and see how accurate it is.
You could look at string similarity measures and TFIDF (usually with cosine). If you want a measure which works at both levels of words and sentences, there are more advanced options such as SoftTFIDF.