---
title: du — Check disk usage
date: 2026-10-17
time: 12:00
model: admin
category: programs
author_type: human
summary: Command for checking disk usage. Three du -sh combinations, three steps to reclaim capacity when logs explode, and actual execution screenshots.
tags: program, File and disk management, du
---

**💬 "du command"**

- **Concept**: An essential Linux command for checking disk usage. It is used to find the culprit folders and files when server storage is full.
- **Output structure**: The default command prints all sub-items in complex detail in KB units, making it hard to read.
- **Recommended practical output**: When you type `du -sh *`, capacity units are summarized in an easy-to-read format such as `45M` or `2.3G`.
- **Left column**: Shows the total capacity actually occupied by the file or folder.
- **Right column**: Shows the name of the target using that capacity.
## 3 Essential Command Combinations

- `du -sh` — Summarize only the total combined capacity of the current folder in a single line
- `du -sh *` — Check the capacity of each item directly under the current folder individually
- `du -sh * | sort -h` — Sort the output so the largest folders appear at the bottom
**💬 "Also tell me one way to apply this"**

**Scenario**: How to resolve a situation where log files explode to GB sizes and the server disk becomes full.

### Step 1: Track down the culprit folder

Move to the log directory and sort the folders by size.

```
cd /var/log && du -sh * | sort -h
```

### Step 2: Target huge files

After entering the culprit folder, dig down to the file level and filter out only files larger than 1GB.

```
du -ah * | grep -E '^[0-9.]+[G]'
```

### Step 3: Free up space safely (key point)

If you delete a running log file with `rm`, the process keeps holding onto it and the disk space is not returned. Use the command below to truncate the file contents to 0 bytes and reclaim space immediately.

```
cat /dev/null > user-activity.log
```

## Actual Execution Screen

This is the result of actually creating a folder on this PC and running `du -sh * | sort -h`. The items get larger toward the bottom, and at the very bottom `logs` is the largest at 2.3G.

![Result of du -sh * | sort -h: sorted by size from 2.4M src to 2.3G logs](https://games.aidebatehub.com/assets/du-demo.png)

Server in actual operation

This is the result of filtering only files larger than 1GB inside that `logs` folder. `user-activity.log` is taking up 1.9G.

![Result of du -ah . | grep -E '^[0-9.]+[G]': 1.9G user-activity.log](https://games.aidebatehub.com/assets/du-logs.png)

---
Source (HTML): https://games.aidebatehub.com/programs/linux/filesystem/du.html
This file is an auto-generated Markdown twin of the DevHub document.