Hi Anonymous Monk,
I am a novice in perl. I am trying to split a data into a summary based on the number of words(or sentences or letter)...

You are welcome to Programming in Perl, and every expert in here started out as a novice. It would be wonderful to see some effort on your part as regard the solution to this your post.
However, I would give you a head up.
Since you are trying to split a "dataset" based on "..number of words, sentences or letters (I prefer based on number of letters)" check usage of split then substr.
You might also want to check How do I post a question effectively?