How to Check Disk Usage in Linux: Simple Commands Explained

To check disk usage in Linux, use the df command to see free and used space on all mounted filesystems. For detailed folder or file size, use the du command.

Syntax

The df command shows disk space usage of mounted filesystems. The du command shows disk usage of files and directories.

• df [options]: Displays disk space usage summary.
• du [options] [path]: Shows size of files and directories at the given path.

bash

df -h

du -sh /path/to/directory

Example

This example shows how to use df -h to display disk usage in a human-readable format and du -sh to check the size of your home directory.

bash

df -h

du -sh ~

Output

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        50G   20G   28G  42% /
/dev/sda2       100G   60G   40G  60% /home

12G	/home/username

Common Pitfalls

Common mistakes include:

• Using df to check folder sizes instead of filesystem usage.
• Not using the -h option, which makes output hard to read.
• Running du without -s can produce too much output.

bash

df

du /home/username

# Better way:
df -h

du -sh /home/username

Quick Reference

Command	Description	Common Option
df	Shows disk space usage of filesystems	-h (human-readable sizes)
du	Shows disk usage of files and directories	-sh (summary, human-readable)
lsblk	Lists block devices and their sizes	-f (shows filesystem info)

Key Takeaways

Use df -h to quickly see disk space usage of all mounted filesystems.

Use du -sh [path] to check the size of a specific directory or file.

Always add -h for human-readable sizes to make output easier to understand.

Avoid using df to check folder sizes; it shows filesystem usage instead.

Use du -s to get a summary instead of a long list of sizes.