Why It’s Important to Get the Size of a Directory in Linux
Are you running out of disk space on your Linux system? One of the first steps to freeing up space is to identify which directories are taking up the most space. In Linux, you can use various methods to get the size of a directory, but which one is the best for your use case? In this article, we’ll explore different ways to get the size of a directory in Linux, so you can choose the one that suits you best.
The Problem
When you need to free up disk space, it’s important to identify which directories are taking up the most space. However, simply listing the contents of a directory with ls
won’t give you an accurate picture of its size. For instance, if a directory contains subdirectories, their sizes won’t be accounted for. Similarly, if a directory contains hard links, ls
will count their sizes multiple times. As a result, it’s essential to use a command that gives you the actual size of a directory.
Overview of Methods
There are several methods to get the size of a directory in Linux, each with its own advantages and disadvantages. In this article, we’ll cover the following methods:
- Using the “du” command
- Using the “tree” command
- Using the “ncdu” command
- Using the “find” and “stat” commands
Each method has its own syntax and customization options, so you can choose the one that best fits your needs.
Using the “du” Command to Get the Size of a Directory in Linux
The du
command in Linux is one of the most commonly used methods to get the size of a directory. It calculates the disk space used by a file or directory and displays the result in blocks. Linuxize provides a helpful guide on using the du
command to get the size of a directory in Linux.
Syntax:
du [OPTION]... [FILE]...
The du
command takes one or more file or directory names as arguments. If no arguments are given, it will display the disk usage of the current directory.
Using the “-h” option to display the size in a human-readable format
The -h
option can be used to display the size in a human-readable format, such as kilobytes (KB), megabytes (MB), or gigabytes (GB). This option makes it easier to read the output.
For example, to get the size of the /usr
directory in human-readable format, run the following command:
du -h /usr
This will display the size of the /usr
directory and its subdirectories in human-readable format.
Using the “-s” option to get the total size of a directory
The -s
option can be used to get the total size of a directory without displaying the size of its subdirectories. This option is useful if you only want to know the total size of a directory. Unix Stack Exchange provides a helpful guide on using the find
and stat
commands along with the paste
and bc
commands to get the total size of a directory.
For example, to get the total size of the /usr
directory, run the following command:
du -sh /usr
This will display the total size of the /usr
directory in human-readable format.
Using the “-c” option to display the grand total of all directories
The -c
option can be used to display the grand total of all directories instead of just the size of each directory. This option is useful if you want to know the total size of multiple directories.
For example, to get the grand total of the /usr
and /var
directories, run the following command:
du -ch /usr /var
This will display the total size of the /usr
and /var
directories, as well as their subdirectories, in human-readable format.
Using pipes to combine the “du” command with other commands
You can combine the du
command with other commands using pipes to further customize the output. For example, you can use the sort
command to sort the directories by size, and the head
command to display the top N largest directories. Stack Abuse provides a helpful guide on using the du
command with pipes to get the top N largest directories.
For example, to display the top 5 largest directories in the /usr
directory, run the following command:
du -h /usr | sort -rh | head -n 5
This will display the top 5 largest directories in the /usr
directory, sorted by size in descending order.
Using the “tree” Command to Get the Size of a Directory in Linux
The tree
command in Linux is another useful tool for getting the size of a directory. Unlike the du
command, tree
displays the directory structure in a tree-like format, making it easier to visualize the file hierarchy. Stack Abuse provides a helpful guide on using the tree
command to get the size of a directory in Linux.
Syntax:
tree [OPTION]... [FILE]...
The tree
command takes one or more file or directory names as arguments. If no arguments are given, it will display the directory structure of the current directory.
Using the “-h” option to display the size in a human-readable format
The -h
option can be used to display the size in a human-readable format, such as kilobytes (KB), megabytes (MB), or gigabytes (GB). This option makes it easier to read the output.
For example, to get the size of the /usr
directory in human-readable format, run the following command:
tree -h /usr
This will display the size of the /usr
directory and its subdirectories in human-readable format.
Using the “-L” option to limit the depth of the tree
The -L
option can be used to limit the depth of the tree. This option is useful if you only want to see the directory structure up to a certain level.
For example, to limit the depth of the tree to 2 levels and get the size of the /usr
directory, run the following command:
tree -h -L 2 /usr
This will display the size of the /usr
directory and its immediate subdirectories in human-readable format.
Using the “-s” option to get the total size of a directory
The -s
option can be used to get the total size of a directory without displaying the size of its subdirectories. This option is useful if you only want to know the total size of a directory.
For example, to get the total size of the /usr
directory, run the following command:
tree -s /usr | awk '{sum += $1} END {print sum}'
This will display the total size of the /usr
directory in bytes.
Using pipes to combine the “tree” command with other commands
You can combine the tree
command with other commands using pipes to further customize the output. For example, you can use the sort
command to sort the directories by size, and the head
command to display the top N largest directories.
For example, to display the top 5 largest directories in the /usr
directory, run the following command:
tree -s /usr | sort -nr | head -n 5
This will display the top 5 largest directories in the /usr
directory, sorted by size in descending order.
Using the “ncdu” Command to Get the Size of a Directory in Linux
The ncdu
command in Linux is a third-party utility that provides an interactive way to get the size of a directory. It displays the disk usage of the directories in a tree-like format, similar to the tree
command. However, ncdu
also allows you to navigate through the directory structure and delete files or directories if needed. PhoenixNAP provides a helpful guide on using the ncdu
command to get the size of a directory in Linux.
Installing the “ncdu” package
To use the ncdu
command, you need to install the ncdu
package first. Use the following command to install it on your system:
sudo apt-get install ncdu
Running the “ncdu” command
To run the ncdu
command, simply type ncdu
followed by the path of the directory you want to scan. For example, to scan the /usr
directory, run the following command:
ncdu /usr
This will display the size of the /usr
directory and its subdirectories in a tree-like format.
Navigating through the directory structure
ncdu
provides an interactive interface that allows you to navigate through the directory structure and view the file sizes. You can use the arrow keys to move up and down the directory tree, and the Enter key to enter a subdirectory. Pressing the q key will exit the program.
Deleting files or directories
ncdu
also allows you to delete files or directories if needed. To delete a file or directory, move the cursor to the file or directory you want to delete and press the d key. This will prompt you to confirm the deletion. Pressing y will delete the file or directory, while pressing n will cancel the operation.
Using the “-r” option to scan a directory recursively
The -r
option can be used to scan a directory recursively. This option is useful if you want to scan all the subdirectories of a directory.
For example, to scan the /usr
directory and all its subdirectories, run the following command:
ncdu -r /usr
This will display the size of the /usr
directory and all its subdirectories in a tree-like format.
Using the “-x” option to exclude certain directories
The -x
option can be used to exclude certain directories from the scan. This option is useful if you want to exclude directories that you know don’t contain any large files.
For example, to scan the /usr
directory and exclude the /usr/share
directory, run the following command:
ncdu -x /usr/share /usr
This will display the size of the /usr
directory and its subdirectories, excluding the
Summary
In this article, we’ve covered three ways to get the size of a directory in Linux using the command line: the du
command, the tree
command, and the ncdu
command.
The du
command is a simple and straightforward way to get the size of a directory. It calculates the disk space used by a file or directory and displays the result in blocks. The tree
command provides a visual representation of the directory structure, making it easier to understand the file hierarchy. The ncdu
command provides an interactive interface that allows you to navigate through the directory structure and delete files or directories if needed.
Each of these commands has its own advantages and disadvantages, depending on your specific use case. By understanding the differences between these commands, you can choose the one that best fits your needs and get the size of a directory in Linux with ease.
Wrapping Up
Getting the size of a directory in Linux is an essential task for system administrators and users alike. By using the du
, tree
, or ncdu
command, you can quickly get an accurate measurement of the disk space used by a file or directory.
In this article, we’ve covered the syntax and usage of each of these commands. We’ve also discussed how to customize the output and provided examples to help you get started.
We hope you found this article helpful. If you have any questions or comments, please feel free to leave them below. And don’t forget to check out our other great content on LINUX HOME PAGE.
Thank you for reading!
Questions
What is the easiest way to get the size of a directory in Linux?
The du
command is the easiest way to get the size of a directory in Linux.
Who can benefit from using the ncdu
command to get the size of a directory in Linux?
The ncdu
command is a great tool for system administrators and users who want an interactive way to get the size of a directory in Linux.
How can I exclude a directory from being scanned by the du
command?
You can exclude a directory from being scanned by the du
command by using the --exclude
option followed by the directory name.
What is the difference between the du
and tree
commands for getting the size of a directory in Linux?
The du
command calculates the disk space used by a file or directory and displays the result in blocks, while the tree
command provides a visual representation of the directory structure.
How can I customize the output of the ncdu
command?
You can customize the output of the ncdu
command by using various command-line options, such as sorting by size or excluding certain files.
What should I do if I get a “permission denied” error when running the du
command?
If you get a “permission denied” error when running the du
command, you may need to run the command with elevated privileges, such as using the sudo
command.