Which of the following is not a shell?

Which command is used to remove an empty directory?

Which operator is used as a shorthand for the test command?

The -r and -R options in the ls command have different functions.

Which option is used with ls to display attributes of the directory? 

Which option in a case statement matches any option not matched by the previous options?

What is the purpose of the $let command in the Linux terminal?

How does the -u option in the ls command sort the files?

What is the correct syntax for performing substitution on a file?

Which of the following are the core functionalities of an operating system kernel?