What does grep do?

What does grep do?

• A. It matches a regular expression against text in a file and prints matching lines.
• B. It lists files in a directory.
• C. It compiles code.
• D. It prints the last line of a file.

Answer: (D)

The concept being tested is how grep performs pattern matching on text and outputs the matching lines. grep searches input (files or standard input) for lines that contain a pattern described by a regular expression and prints those entire lines that match. For example, running grep 'foo' file.txt will display every line in file.txt that includes the sequence foo. It doesn’t list files like a directory listing tool, it doesn’t compile code, and it doesn’t just print the last line—that last behavior would come from a different command like tail. If you need more control, you can adjust what’s printed with options, such as showing line numbers, ignoring case, or printing only the matching portion of a line.

The concept being tested is how grep performs pattern matching on text and outputs the matching lines. grep searches input (files or standard input) for lines that contain a pattern described by a regular expression and prints those entire lines that match. For example, running grep 'foo' file.txt will display every line in file.txt that includes the sequence foo. It doesn’t list files like a directory listing tool, it doesn’t compile code, and it doesn’t just print the last line—that last behavior would come from a different command like tail. If you need more control, you can adjust what’s printed with options, such as showing line numbers, ignoring case, or printing only the matching portion of a line.