Final answer:
The command 'find / -xdev -nouser' is used to search for files with no associated user. It starts the search from the root directory and excludes mounted file systems.
Step-by-step explanation:
The command find / -xdev -nouser is used to search for files with no associated user. This means that it will look for files that have been detached from their owner, typically when a user account is deleted. The / specifies that the search should start from the root directory and -xdev restricts the search to the current file system, excluding any mounted file systems.