There are softwares already that helps to replace a string in a file. Suppose, if you’re making a program that requires saving some data in to a file. By “adding”, the program is actually replacing a word. Let’s see how it’s done in PHP & Python. This is the file where we are going to replace the word : thisWord I got thisWord for making it thatWord replace thisWord already my friend. We replace the word “thisWord” to “thatWord” containing in this file. PHP <?php $file...