The comparison operators for test that work on elements in the file system are -d and -f. The -d operator tests if a given file name refers to a directory, and returns true if it does. The -f operator tests if a given file name refers to a regular file, and returns true if it does. These operators are part of the topic 105.3: Perform basic file management, which is one of the objectives of the LPI Linux Administrator - 102 exam12. Reference: 1: LPI Linux Administrator - 102 (LPIC-1) 2: Exam 102 Objectives