What is the purpose of the 'grep' command?

The primary purpose of the 'grep' command is to search for specific patterns within files. It stands as a powerful utility in Unix-like operating systems, allowing users to search through text for lines that match a given regular expression. This functionality is incredibly useful for parsing log files, analyzing data, or any situation where finding specific information within files is necessary. The name 'grep' itself is derived from a command used in the text editor ed, which stands for "global regular expression print." This highlights its core functionality, focusing on pattern matching and retrieval of text.

In contrast, the other choices represent different functionalities that are not related to 'grep.' Displaying system processes pertains to commands like 'ps' or 'top,' sorting files relates to the 'sort' command, and compressing files is handled by commands like 'gzip' or 'tar.'