How do you change to the parent directory in a command-line interface?

To change to the parent directory in a command-line interface, the use of the command "cd .." is the correct approach. The command "cd" stands for "change directory," and when followed by "..", it instructs the system to move up one level in the directory hierarchy. The ".." notation is a standard way in Unix-like operating systems to refer to the parent directory of the current working directory.

This command is fundamental in navigating through the file system. For example, if your current directory is "/home/user/documents," executing "cd .." will take you to "/home/user."

The other options suggest alternatives that do not achieve the intended result. "cd ../" would change to the parent directory as well, but it also implies moving into the parent directory while allowing for possibly specifying a subdirectory afterwards, which is not necessary for simply changing to the parent directory. The terms "parent" and "back" do not correspond to any valid directory navigation commands, as there are no built-in expressions in the command-line interface that recognize them in this context. Hence, they would not perform any action related to changing directories.