Disk Usage Analysis (df, du)

Disk usage analysis in Ubuntu can be performed using the df and du commands. Here's an explanation of both commands along with examples and outputs:

1. df (Disk Free)

The df command reports the amount of disk space used and available on all mounted filesystems. It’s commonly used to get an overview of the entire disk usage on your system.

Basic Usage:

df -h

Explanation:

• -h stands for "human-readable," which formats the output in a way that's easier to read (e.g., MB, GB).

Example Output:

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        50G   15G   32G  33% /
/dev/sda2       100G   45G   51G  47% /home
tmpfs           1.6G  4.0K  1.6G   1% /run/user/1000

Explanation of Output:

• Filesystem: The name of the filesystem or partition.
• Size: Total size of the filesystem.
• Used: Amount of space used.
• Avail: Available space.
• Use%: Percentage of the disk space used.
• Mounted on: The mount point or directory where the filesystem is mounted.

2. du (Disk Usage)

The du command is used to estimate file space usage. It provides more detailed information about the disk space usage of files and directories within a specific directory.

Basic Usage:

du -h /path/to/directory

Explanation:

• -h stands for "human-readable," making the sizes easier to read.

Example Output:

4.0K    /home/user/.config
8.0K    /home/user/Documents/Project
20M     /home/user/Documents
45G     /home/user

Explanation of Output:

• First Column: Size of the directory or file.
• Second Column: Path to the directory or file.

Combined Usage Example:

To get a quick overview of how much space a specific directory is using, you can combine df and du.

Example:

df -h /home/user && du -sh /home/user/Documents

Output:

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda2       100G   45G   51G  47% /home

20M     /home/user/Documents

Summary

• df gives an overview of the disk usage on mounted filesystems.
• du provides detailed disk usage information for specific files or directories.

These commands are essential for monitoring and managing disk space, especially on systems where storage is limited.