What does the grep command do?

The grep command is a powerful and widely used utility in Unix/Linux systems that searches for specific strings or patterns within files. When you run grep, you specify the string you want to search for and the file or files you want to search through. The command then scans the content of those files and prints lines that contain the specified string. This functionality makes grep an essential tool for programmers and system administrators who need to quickly locate text within large amounts of data or log files.

Its versatility extends to using regular expressions, which allows for complex search patterns, enhancing the effectiveness of text searching in scripts and command-line operations. Given its primary purpose of searching for strings, this makes it the correct answer to the question regarding the functionality of the grep command.