du

Additional Notes

du shows how much disk space files and directories use. It is the command you use after df tells you a filesystem is full and you need to find what is taking space.

By default, du works recursively, so use depth limits or summary mode when checking large directories.

Syntax

du [options] [file-or-directory...]

Parameters

• options: Flags that change how du behaves.
• device: Disk, partition, volume, or filesystem path to inspect or modify.
• target: Mount point, file, or storage object used by the operation.

Common Options

• -h, --human-readable: Show readable sizes.
• -s, --summarize: Show only a total for each argument.
• -a, --all: Show files as well as directories.
• -c, --total: Show a grand total.
• -d N, --max-depth=N: Limit directory depth.
• --apparent-size: Show apparent file size instead of disk blocks used.
• -x, --one-file-system: Do not cross filesystem boundaries.

Examples

du -sh *

Show summary sizes for items in the current directory.

du -sh /var/log

Show total disk usage of /var/log.

du -h -d 1 /home/rani

Show one level of directory sizes.

du -ah . | sort -h | tail

Find large files and directories under the current path.

du -ch *.iso

Show sizes for ISO files and a total.

du -xhd 1 /

Show top-level usage under / without crossing into other filesystems.

Practical Notes

• du can take time on large trees because it walks files.
• Use du -sh * as a quick first step.
• Use sort -h to sort human-readable sizes.
• du and df can disagree because deleted open files, reserved blocks, and filesystem metadata matter.
• For interactive cleanup, ncdu is often easier if installed.