This command redirects the output of ls to standard error, which is file descriptor 2 by default. The syntax of the command is:

ls >& file_descriptor

The ls command is a utility that lists the files and directories in the current working directory or a specified directory. The >& symbol is a redirection operator that redirects the standard output of a command to another file descriptor, which can be a file, a device, or another stream. The file_descriptor is the number of the file descriptor to which the output is redirected.

Therefore, the command ls >&2 will run the ls command and redirect its output to file descriptor 2, which is standard error. This means that the output of ls will not be displayed on the screen, but sent to the standard error stream, which can be used for error handling or logging purposes.

The other commands are incorrect for the following reasons:

A, ls >-1: This command will not redirect the output of ls to standard error, but it will cause an error. The > symbol is a redirection operator that redirects the standard output of a command to a file or device, overwriting any existing content. The -1 argument is not a valid file name or device name, and it will cause the shell to report an error and exit.

B, ls <

D, ls >>2: This command will not redirect the output of ls to standard error, but it will append the output of ls to a file named 2. The >> symbol is a redirection operator that redirects the standard output of a command to a file or device, appending to any existing content. The 2 argument is the name of the file to which the output is appended. If the file does not exist, it will be created. The command will not display anything on the screen, but write the output of ls to the file 2.

E, ls |error: This command will not redirect the output of ls to standard error, but it will pipe the output of ls to another command named error. The | symbol is a pipe operator that redirects the standard output of one command to the standard input of another command. The error argument is the name of the command that receives the output of ls as its input. However, there is no such command named error in the Linux system, and the shell will report an error and exit.