Master Linux Disk Usage: How to Use df and du Commands Effectively

df command

Check disk space usage (cannot view the size of a specific directory). The basic syntax is df [option].

-h Output in a human‑readable format (e.g., 10K, 10M, 10G).

-k Output in kilobytes.

-m Output in megabytes.

-a List all filesystems, including those with size 0.

-i Show inode information.

-T Display the filesystem type of each partition.

Example: view partition usage and filesystem type:

df -hT

The command shows each partition's total, used, and available capacity.

To view the disk usage of the partition containing a specific directory:

df -h nodedemo/

To output inode information of the filesystem:

df -ih

du command

Display the disk space occupied by files or directories. Syntax: du [option] file/directory.

-h Human‑readable output (e.g., 10K, 10M).

-s Show only the total size of the specified file or directory (default unit is K).

Show the size of the current directory:

du -hs

Show the size of a specific directory or file:

du -hs nodedemo/

du -hs nodedemo/Dockerfile

Show the size of all files in the current directory:

du -hs ./*

Note the difference between the following usages:

du -hs xxxx          # Shows total size of the directory without listing each file

du -hs xxxx/*        # Lists size of each file and subdirectory under xxxx

Warning: Do not run du indiscriminately on large directories, as it will traverse and list every file, potentially overwhelming the output.