What is the purpose of the 'df' command?

The command 'df' stands for "disk free" and is primarily used to show the amount of disk space used and available on file systems. It provides an overview of file systems in a Linux environment, detailing how much space is utilized and how much is free, along with the file system types and their mount points.

When you run the 'df' command, it outputs a list of all mounted file systems along with critical information such as the total size, used space, available space, and the mount points for those file systems. This is particularly useful for system administrators who need to monitor disk space usage and manage file systems effectively.

The choice that indicates displaying file systems and their mount points does reflect a key aspect of the information provided by 'df', but the command's primary focus is on disk usage information. Hence, while the answer covers part of what 'df' does, emphasizing the disk usage aspect presents a more accurate understanding of the command's main purpose.