Why use regular expressions?

Generally, all editors have the ability to perform search-and-replace operations. Some editors can only search for patterns, others can also replace them, and others can also print the line containing that pattern. A regular expression goes many steps beyond this simple search, replace, and printing functionality, and hence it is more powerful and flexible. We can search for a word of a certain size, such as a word that has four characters or numbers. We can search for a word that ends with a particular character, let's say e. You can search for phone numbers, email IDs, and so on, and can also perform validation using regular expressions. They simplify complex pattern-matching tasks, and hence form an important part of AWK programming. Other regular expression variations also exist, notably those for Perl.