du (Disk Usage)
The du command is used to estimate file space usage. It tracks the space utilized by each file and directory, making it an essential tool for identifying storage hogs and managing disk space effectively.
1. Basic Usage
du [options] [directory/file]
2. Key Options
| Option | Name | Description |
|---|---|---|
-h |
human-readable | Displays sizes in KB, MB, or GB for easy reading. |
-s |
summarize | Shows only a total for each specified argument. |
-a |
all | Shows counts for all files, not just directories. |
-d N |
max-depth | Limits the display to N levels deep into the directory tree. |
-c |
total | Produces a grand total at the bottom of the output. |
3. Practical Examples
① Checking the total size of the current folder
du -sh .
② Checking sizes of subdirectories at a specific depth
du -h -d 1 /home/user/
③ Finding the top 10 largest directories
du -ah /var | sort -rh | head -n 10
4. [Tip] Why the numbers might differ
Sometimes du shows a different value than ls -l. This is because du reports the actual disk blocks consumed, which includes file system overhead, while ls reports the apparent size of the file content.