What command do you use to view the structure of system directory hierarchies?

The `tree` command is specifically designed to list the contents of directories and their subdirectories in a recursive, tree-like format. This command provides a clear, visual representation of the entire directory structure.

This is a syntactically incorrect command combination; `fee` is not a standard Linux command.

`ls -t` lists directory contents sorted by modification time, not in a hierarchical tree structure.

`ls tree` would attempt to list a file or directory literally named "tree" (or report an error if it doesn't exist) and does not provide a hierarchical view.