How to check disk usage?

Checking Disk Usage in Linux

Disk usage is an important aspect of system administration and resource management in Linux. Knowing how to check disk usage can help you identify storage issues, plan for future storage needs, and optimize your system's performance.

The `du` Command

The primary command used to check disk usage in Linux is the du (disk usage) command. This command provides detailed information about the disk space used by files and directories on your system.

Here's the basic syntax for using the du command:

du [options] [file or directory]

Some common options for the du command include:

-h: Displays the disk usage in human-readable format (e.g., MB, GB)
-s: Displays the total disk usage for a file or directory
-c: Displays the grand total of all the disk usage
-d <depth>: Limits the depth of the directory tree to the specified number of levels

For example, to check the disk usage of the current directory, you can use the following command:

du -h

This will display the disk usage of each file and directory within the current directory, in a human-readable format.

To get the total disk usage of the current directory, you can use the following command:

du -sh

This will display the total disk usage of the current directory in a human-readable format.

The `df` Command

Another useful command for checking disk usage is the df (disk free) command. This command provides information about the available and used space on your file system.

Here's the basic syntax for using the df command:

df [options] [file or directory]

Some common options for the df command include:

-h: Displays the disk usage in human-readable format (e.g., MB, GB)
-i: Displays information about the inode usage
-T: Displays the file system type

For example, to check the disk usage of all mounted file systems, you can use the following command:

df -h

This will display the total size, used space, available space, and percentage of used space for each mounted file system.

Visualizing Disk Usage with Graphical Tools

While the du and df commands provide a textual representation of disk usage, you can also use graphical tools to visualize disk usage. One popular tool is ncdu (NCurses Disk Usage), which provides a user-friendly, interactive interface for exploring disk usage.

To install and use ncdu, you can follow these steps:

Install ncdu using your Linux distribution's package manager. For example, on Ubuntu, you can use the following command:
```
sudo apt-get install ncdu
```
Run the ncdu command in your terminal:
```
ncdu
```
Navigate through the directory tree using the arrow keys, and press Enter to explore a directory in more detail.
Press q to quit the ncdu application.

The ncdu tool provides a visual representation of disk usage, making it easier to identify large files and directories that are consuming the most disk space.

Conclusion

Checking disk usage is an essential skill for Linux system administrators and users. The du and df commands provide powerful command-line tools for analyzing disk usage, while graphical tools like ncdu offer a more user-friendly interface. By understanding how to effectively check disk usage, you can better manage your system's storage resources and optimize its performance.