It depends how much you want to get into it and how big the project is. If it's finding only identical phrases or text, most word processors support this, and finally a lot of programming ide's support regular-expression searching (http://en.wikipedia.org/wiki/Regular_expression). On the other hand if you are looking to find reworded or similar paragraphs and/or excerpts and want to automate this (rather than substringing and searching for variations manually), than I would recommend you look at http://www.nltk.org/

NLTK is a toolkit that integrates a whole range of language manipulation, sorting and tagging tools - I realize it may be more in depth than you want to go (but it is quite easy to learn and has a very good beginner friendly documentation http://www.nltk.org/book/).

I'll let others comment on more generic and perhaps quicker to handle at a glance tools, as I have no experience with those.

It depends how much you want to get into it and how big the project is. If it's finding only identical phrases or text, most word processors support this, and finally a lot of programming ide's support regular-expression searching (http://en.wikipedia.org/wiki/Regular_expression). On the other hand if you are looking to find reworded or similar paragraphs and/or excerpts and want to automate this (rather than substringing and searching for variations manually), than I would recommend you look at http://www.nltk.org/

NLTK is a toolkit that integrates a whole range of language manipulation, sorting and tagging tools - I realize it may be more in depth than you want to go (but it is quite easy to learn and has a very good beginner friendly documentation http://www.nltk.org/book/).

I'll let others comment on more generic and perhaps more 'use out of the box' type tools, as I have no experience with those.