From : Blog Entry>>Sean’s Blog Entry
A grep utility is a tool which can be used to run regular expression (regex) searches through the text of multiple files.  If you have a set of hundreds or thousands of PDFs or text files, and you want to extract text from these files which matches a regex pattern, a grep utility can run the search quickly, and export the matching text to a new file. PowerGrep is a widely used grep utility with a graphical interface.  A single user license can be purchased for less than $200.  The open source grep [More]