What does the 'grep' command do?

The 'grep' command is a powerful utility in Unix-like operating systems that is specifically designed to search for specific patterns within files. It stands for "Global Regular Expression Print," highlighting its functionality in searching text using regular expressions. When executed, it scans the contents of files or standard input, matching the specified pattern, and then displays the lines that contain that pattern.

This command is commonly used for tasks such as searching through log files for error messages, looking for specific text within code files, or filtering output from other commands. Its ability to work with regular expressions allows for complex pattern matching, making it a versatile tool for text processing.

The other options do not accurately reflect the primary function of 'grep.' The command does not modify files, display system information, or delete lines from files; its sole purpose is to search and print matching lines from the input based on the given pattern. This makes the choice that identifies grep's function as a search tool correct.