Which command helps in finding out disk usage of directories?

The command that helps in finding out disk usage of directories is "du," which stands for "disk usage." This command is specifically designed to summarize and report the amount of disk space used by files and directories. When you run "du" followed by a directory path, it provides a detailed view of the space consumed by that directory and its subdirectories, allowing you to identify which parts of the filesystem are using the most storage.

In practical use, "du" can include options to customize its output, such as displaying sizes in human-readable formats or providing summaries for each directory. This makes it a powerful tool for system administrators and users who need to manage disk space effectively.

In contrast, "df" shows the amount of disk space used and available on filesystems but does not drill down into individual directories' usage. The "ls -l" command lists files in a directory with detailed permissions and other file attributes but does not provide information about disk usage. Lastly, "fdisk" is a utility for managing disk partitions and is unrelated to disk usage reporting.