How can you check the disk usage of a directory in Linux?

When you want to check the disk usage of a directory in Linux, the most appropriate command to use is "du" (disk usage). This command provides a summary of disk space used by files and directories, allowing you to see how much space a specific directory occupies on the file system.

The "du" command can be used in various ways to obtain detailed information. For example, you can run it with options to display sizes in a more human-readable format or to summarize the total size of a directory without listing each individual file. This is particularly useful for managing space and understanding disk usage on a system.

In contrast, while the "df" command shows the available disk space on entire filesystems rather than specific directories, "ls" is for listing files in a directory and their attributes. The term "diskusage" is not a standard command in Linux, which makes it non-applicable here. Therefore, "du" is the correct choice for checking the disk usage of a directory.