Find space usage linux

Classic SysAdmin: How to Check Disk Space on Linux from the Command Line

This is a classic article written by Jack Wallen from the Linux.com archives. For more great SysAdmin tips and techniques check out our free intro to Linux course.

Quick question: How much space do you have left on your drives? A little or a lot? Follow up question: Do you know how to find out? If you happen to use a GUI desktop (e.g., GNOME, KDE, Mate, Pantheon, etc.), the task is probably pretty simple. But what if you’re looking at a headless server, with no GUI? Do you need to install tools for the task? The answer is a resounding no. All the necessary bits are already in place to help you find out exactly how much space remains on your drives. In fact, you have two very easy-to-use options at the ready.

In this article, I’ll demonstrate these tools. I’ll be using Elementary OS, which also includes a GUI option, but we’re going to limit ourselves to the command line. The good news is these command-line tools are readily available for every Linux distribution. On my testing system, there are a number of attached drives (both internal and external). The commands used are agnostic to where a drive is plugged in; they only care that the drive is mounted and visible to the operating system.

With that said, let’s take a look at the tools.

df

The df command is the tool I first used to discover drive space on Linux, way back in the 1990s. It’s very simple in both usage and reporting. To this day, df is my go-to command for this task. This command has a few switches but, for basic reporting, you really only need one. That command is df -H. The -H switch is for human-readable format. The output of df -H will report how much space is used, available, percentage used, and the mount point of every disk attached to your system (Figure 1).

What if your list of drives is exceedingly long and you just want to view the space used on a single drive? With df, that is possible. Let’s take a look at how much space has been used up on our primary drive, located at /dev/sda1. To do that, issue the command:

The output will be limited to that one drive (Figure 2).

You can also limit the reported fields shown in the df output. Available fields are:

• source — the file system source
• size — total number of blocks
• used — spaced used on a drive
• avail — space available on a drive
• pcent — percent of used space, divided by total size
• target — mount point of a drive

Let’s display the output of all our drives, showing only the size, used, and avail (or availability) fields. The command for this would be:

The output of this command is quite easy to read (Figure 3).

The only caveat here is that we don’t know the source of the output, so we’d want to include source like so:

df -H --output=source,size,used,avail

Now the output makes more sense (Figure 4).

du

Our next command is du. As you might expect, that stands for disk usage. The du command is quite different to the df command, in that it reports on directories and not drives. Because of this, you’ll want to know the names of directories to be checked. Let’s say I have a directory containing virtual machine files on my machine. That directory is /media/jack/HALEY/VIRTUALBOX. If I want to find out how much space is used by that particular directory, I’d issue the command:

du -h /media/jack/HALEY/VIRTUALBOX

The output of the above command will display the size of every file in the directory (Figure 5).

So far, this command isn’t all that helpful. What if we want to know the total usage of a particular directory? Fortunately, du can handle that task. On the same directory, the command would be:

du -sh /media/jack/HALEY/VIRTUALBOX/

Now we know how much total space the files are using up in that directory (Figure 6).

You can also use this command to see how much space is being used on all child directories of a parent, like so:

The output of this command (Figure 7) is a good way to find out what subdirectories are hogging up space on a drive.

The du command is also a great tool to use in order to see a list of directories that are using the most disk space on your system. The way to do this is by piping the output of du to two other commands: sort and head. The command to find out the top 10 directories eating space on a drive would look something like this:

du -a /media/jack | sort -n -r | head -n 10

The output would list out those directories, from largest to least offender (Figure 8).

Not as hard as you thought

Finding out how much space is being used on your Linux-attached drives is quite simple. As long as your drives are mounted to the Linux system, both df and du will do an outstanding job of reporting the necessary information. With df you can quickly see an overview of how much space is used on a disk and with du you can discover how much space is being used by specific directories. These two tools in combination should be considered must-know for every Linux administrator.

And, in case you missed it, I recently showed how to determine your memory usage on Linux. Together, these tips will go a long way toward helping you successfully manage your Linux servers.

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5 Linux commands to check free disk space

Keeping track of disk utilization information is on system administrators’ (and others’) daily to-do list. Linux has a few built-in utilities that help provide that information.

Linux df command

The df command stands for «disk-free,» and shows available and used disk space on the Linux system.

df -h shows disk space in human-readable format

df -a shows the file system’s complete disk usage even if the Available field is 0

df -T shows the disk usage along with each block’s filesystem type (e.g., xfs, ext2, ext3, btrfs, etc.)

df -i shows used and free inodes

You can get this information in a graphical view using the Disks (gnome-disk-utility) in the GNOME desktop. Launch it to see all disks detected by your computer, and click a partition to see details about it, including space used and space remaining.

Linux du command

du shows the disk usage of files, folders, etc. in the default kilobyte size

du -h shows disk usage in human-readable format for all directories and subdirectories

du -a shows disk usage for all files

du -s provides total disk space used by a particular file or directory

The following commands will check your total space and your utilized space.

This information can be represented visually in GNOME with the Disk Usage application, or with Filelight in the KDE Plasma desktop. In both applications, disk usage is mapped to concentric circles, with the middle being the base folder (usually your /home directory, but it’s up to you) with each outer ring representing one directory level deeper. Roll your mouse over any segment for detailed information about what’s taking up space.

Linux ls -al command

ls -al lists the entire contents, along with their size, of a particular directory

Linux stat command

stat displays the size and other stats of a file/directory or a filesystem.

Linux fdisk -l command

fdisk -l shows disk size along with disk partitioning information

These are most of the built-in utilities for checking file space in Linux. There are many similar tools, like Disks (GUI), Ncdu, etc., that also show disk space utilization. Do you have a favorite tool that’s not on this list? Please share in the comments.

This article was originally published in July 2018 and has been updated to include additional information.

Check used disk space on Linux with du

Find out how much disk space you’re using with the Linux du command.

Use df to check free disk space on Linux

Find out how much Linux disk space you have left with the df command.

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