The command "ls" is a standard utility in many operating systems, particularly in Unix-like systems such as Linux and macOS. It is used to list the files and directories in a specified directory. By default, "ls" displays the names of the files and folders in the current working directory. Users can modify the output of "ls" with various options, such as "-l" for a detailed list that includes file permissions, sizes, and modification dates. Other options, like "-a," show hidden files that start with a dot. This command is essential for navigating and managing files in the command line interface.