Rat sheets are evaluations of how well you believe your team worked the previous week. Perl has regular expressions embedded in the language. R. e (regular expressions) are a powerful tool for text processing. They allow for the description and parsing of text. With additional support, tools employing regular expressions can modify text and data. Check many files to confirm that each file the word setsize appears exactly as often as. Or that there are the same number of malloc() and free() It can be thought of as checking your code, so that it has the same number of opening and closing braces. Check any number of files and report any occurrence of double words (e. g. the the) Should be case insensitive (ii. e. the the). If you were checking html code then you would have to disregard the html tags. **all regular expressions uses the same symbols - no matter the tool.