What utility would you use in Linux to find specific keywords within email messages?

The utility that can be used in Linux to find specific keywords within email messages is GREP. This powerful command-line tool searches through text files for lines that match a specified pattern or keyword. When applied to email messages—whether stored in plain text files or output from other commands—GREP can efficiently locate and display occurrences of certain keywords, allowing for quick data retrieval and analysis.

In the context of email messages, GREP can filter through large volumes of text to pinpoint relevant information, which is especially useful during investigations or evidence recovery processes. Its versatility and effectiveness in text searching make it an essential tool for anyone working with text files on Linux systems.

The other options mentioned, such as STRINGS, SU, and BIND, do not serve the same purpose. STRINGS extracts printable strings from binary files, making it more suitable for different file types rather than specifically targeting keywords in text messages. SU is used for switching users and does not provide any searching functionality. BIND is associated with DNS management and is unrelated to file or text searching tasks. Therefore, GREP stands out as the most appropriate choice for this particular task.