Which command in Linux is used to estimate and display the disk space usage of…

Concept

Linux disk-related commands split into two distinct jobs. One job reports usage at the level of individual files and directory trees (how much space a given set of files occupies). The other job reports usage at the level of whole mounted filesystems (how much total space and free space a partition has). The first is what “estimate and display the disk space usage of files and directories” asks for.

Application

The du command (short for “disk usage”) walks a file or directory tree and reports the space occupied by each item, summarising recursively. Running du -sh /path prints a single human-readable total for that path, which is exactly the per-file/per-directory estimate the question describes.

Contrast

• df reports free and used space for whole mounted filesystems, not for individual files or directories.

• ls lists directory contents (names, permissions, sizes of entries) but does not total or estimate tree usage.

• top is a live process/CPU/memory monitor and reports nothing about disk space.

• mkdir creates a new directory and performs no measurement at all.

So the command that estimates and displays disk-space usage of files and directories is du.