du

Understanding the Basics of du

At its core, du summarizes disk usage. Its simplest form is:

du -sh /path/to/directory

• du: Invokes the disk usage command.
• -s: Produces a single total for each argument. Without this, du lists usage for each subdirectory.
• -h: Prints sizes in human-readable format (e.g., KB, MB, GB).
• /path/to/directory: Specifies the directory you want to analyze.

Let’s say you want to see the total size of your home directory:

du -sh ~

This will output a single line showing the total size of your home directory in a human-readable format.

Exploring du’s Options

The du command offers a range of options to fine-tune your analysis:

1. Detailed Directory Listing:

Omitting the -s option provides a detailed breakdown of disk usage for each subdirectory within the specified path:

du -h /path/to/directory

This will list each subdirectory and its size, making it easy to pinpoint large directories.

2. Sorting by Size:

To sort the output by size, use the -h (human-readable) and -c (total) options along with sort:

du -sh * | sort -rh

This command lists all files and directories in the current directory, sorts them in reverse order (largest to smallest) and displays the total disk usage at the end. Note the * acts as a wildcard for all files and directories in current location.

3. Specifying File Types:

While du primarily focuses on directories, you can analyze individual files:

du -sh my_large_file.txt

4. Finding the Top 10 Largest Directories:

Combining du, sort, and head, you can quickly identify the 10 largest directories:

du -sh /* | sort -rh | head -n 10

This command analyzes all directories in the root directory (/), sorts them by size in reverse order, and displays the top 10. Caution: Running this on the root directory can take some time.

5. Excluding Specific Files or Directories:

The --exclude option allows you to ignore specific files or directories during the analysis. For example, to exclude the /tmp directory:

du -sh --exclude=/tmp /path/to/directory

6. Maximum Depth:

The -d option lets you specify the maximum depth to traverse when analyzing subdirectories. For instance, to only analyze the immediate subdirectories:

du -d 1 -h /path/to/directory

These examples demonstrate the versatility of the du command. By combining different options, you can tailor your analysis to your specific needs, effectively managing disk space and identifying potential issues.