Tips to check Disk Space in Linux [10 Methods]


Written by - Deepak Prasad

So are you wondering, How to check disk space in Linux command line? Let me help you!

In Linux, checking disk space is an essential task for system administrators to monitor the usage of available storage space. The process involves inspecting the current amount of used and free space on the hard drive, which is important to ensure that the system can continue to operate optimally. There are various methods to check disk space in Linux, and in this response, we will explore some of the most commonly used ones.

 

Different methods to check disk space in Linux

Here are the different methods to check disk space in Linux, explained in points:

Command Line Interface

  • Use the built-in Linux utility command 'df'
  • Syntax: 'df [options] [filesystem]'
  • Options include '-h' to display output in a human-readable format and '-T' to show file system type

Graphical User Interface

  • Most Linux distributions come with a file manager that displays disk usage information
  • For example, the Nautilus file manager in Ubuntu displays disk space information in the lower-left corner of the window
  • Other file managers, such as Thunar in Xubuntu and Dolphin in KDE, have similar features

Third-Party Disk Space Monitoring Tools

  • Install third-party tools to provide more detailed information about disk usage
  • Popular tools include Baobab, DiskUsage, and Ncdu
  • These tools can provide information on which directories and files are taking up the most space

 

Here are some of the CLI tools which you can use to check disk space in Linux

 

1. df command

The df command to check disk space in Linux is widely used by Linux Administrators. It is a built-in utility that displays the amount of free and used disk space on the file system. It is used to report the amount of available and used disk space on the file system, including file systems mounted on remote machines. It can be used to check disk space.

By default, the df command displays the sizes of the file systems in 1-kilobyte blocks and the available and used space in the same units. The output of df includes the file system's device name, total size, used space, available space, percentage of used space, and the mount point of the file system.

You can use df with -Th to print the partition type and the partition size in human readable format. This command will show you the total available, used and free space per partition.

Check disk space in Linux using 10 different CMDs

You can also use other arguments such as -i to print the available, used and free inode count per partition:

Check disk space in Linux using 10 different CMDs

We can use awk to get the desired output, you can modify this based on your requirement. Currently it prints total size of the partition.

# df -h | awk '{printf "%-20s %s\n", $1, $2}'
Filesystem           Size
devtmpfs             1.8G
tmpfs                1.9G
tmpfs                745M
/dev/mapper/rl-root  18G
/dev/sda1            1014M
tmpfs                373M
overlay              18G
tmpfs                373M
overlay              18G

You can check the man page of df command for other supported arguments to check disk space in different formats.

 

2. fdisk command

fdisk is another very handy utility for system administrators. fdisk is a user interactive program mostly used for creation and manipulation of partition tables such as creating, deleting, modifying partitions. But we can also use this utility to list the available disks connected to the Linux system along with the respective disk size.

Here is a snippet of output from command "fdisk -l"
Check disk space in Linux using 10 different CMDs

As you can see from the output, I have a disk /dev/sda with a size of 15GB. The output also shows more details about this disks wherein it contains two partitions /dev/sda1 and /dev/sda2.

The output of fdisk -l can be quiet long so if you just wish to check the disk space then you can use this command:

~]# fdisk -l | awk '$1=="Disk" && $2 ~ /^\/dev\/.*/ {print $2 $3 $4}'
/dev/sda:15GiB,
/dev/sdb:8GiB,
/dev/mapper/rhel-root:14GiB,
/dev/mapper/rhel-swap:512MiB,

Here I have combined fdisk with awk to only print required sections. So I have two disks with 15GB and 8GB each, while I have two LVM partitions which are most likely part of these disks with a size of 14GB and 512MB.

 

3. parted command

parted is another alternative to fdisk and is also used for manipulating disk partitions and is available by default in many Linux distributions such as Ubuntu. It is useful for creating space for new operating systems, reorganizing disk usage, and copying data to new hard disks. But we can also use it to check disk space on Linux.

Similar to fdisk, we can use parted -l to list all the available disks along with their respective size:

Check disk space in Linux using 10 different CMDs

If you compare the output of parted with fdisk, here we only get the available disk and their size and the LVM details are missing which is a good thing as we only wanted to check the disk space.

We can also use awk with parted to further only print required output:

~]# parted -l | awk '$1=="Disk" && $2 ~ /^\/dev\/.*/ {print $2 $3 $4}'
/dev/sda:16.1GB
/dev/sdb:8590MB

 

4. du command

The du command stands for "disk usage", and it is a standard Linux command that is used to estimate the space used by a file or directory on a file system. It can be used to determine which files or directories are taking up the most disk space. du gives you flexibility to check disk space by folder in Linux.

The basic syntax of the du command is as follows:

du [options] [directory or file name]

By default, du displays the disk usage of each directory and subdirectory in the current directory. If you specify a directory or file name, it will display the disk usage of that particular directory or file.

Here are some commonly used options for the du command:

  • -h: Display the disk usage in a human-readable format, such as "1.2K" or "3.4M".
  • -s: Display only a total sum of the disk usage for the specified directory or file.
  • -c: Display a grand total of the disk usage for all the directories and files that are specified.
  • -a: Display the disk usage for all files and directories, including hidden files and directories.

Here are some example demonstrating different scenarios to check file system size using du command:

To check the disk usage of a particular directory:

du -sh /path/to/directory

To check disk space used by a single file:

du -h file.txt

To check disk space used by a directory and all its subdirectories:

du -h directory/

To check the total disk space used by a directory and all its subdirectories:

du -h -c directory/

To display the sizes of all files and directories in a directory (not just directories):

du -h -a directory/

 

To check size of all the files under a partition recursively

Check disk space in Linux using 10 different CMDs

 

To get total summary of size of files in a partition or directory

We can use du -c to print a total or summary of all the file size under provided directory or partition.

~]# du -sch /etc/iscsi/*
4.0K    /etc/iscsi/initiatorname.iscsi
16K     /etc/iscsi/iscsid.conf
20K     total

 

To sort the output based on file size

By default the du command will print the size of the file based on the first available directory or sub-directory. So the output is not sorted and it can be a tedious task to go through the long list. We can combine du with sort command do sort the output based on the file size.

Check disk space in Linux using 10 different CMDs

Here we have used du with sort -hr where -h is used to compare human readable numbers such as 2K, 1G, 4M etc while -r is used to reverse the order of search.

 

To print file size larger than specified size

By default du will print the size of every file found under a partition or directory. We can add a threshold to print files higher than a certain size.

For example here we are printing the files with size higher than 1MB under /var/log

~]# du -ach -t 1M /var/log/* | sort -hr
19M     total
8.9M    /var/log/anaconda
4.2M    /var/log/anaconda/lvm.log
3.2M    /var/log/anaconda/journal.log
1.9M    /var/log/dnf.librepo.log
1.6M    /var/log/audit/audit.log
1.6M    /var/log/audit

For more list of supported options check the man page of du command.

 

5. lsblk command

lsblk lists information about all available or the specified block devices. The lsblk command reads the sysfs filesystem and udev db to gather information. If the udev db is not available or lsblk is compiled without udev support than it tries to read LABELs, UUIDs and filesystem types from the block device.

We can use lsblk with -o LIST or --output LIST to get desired columns based on the value of LIST. Use lsblk --help to get a list of all supported columns.

We will use name, fstype, size, mountpoint LIST for our example. Although using only size and name was enough but to give more detailed output I am using additional list options.

~]# lsblk -o NAME,SIZE,FSTYPE
NAME         SIZE FSTYPE
sda           20G 
├─sda1         1G xfs
└─sda2      18.5G LVM2_member
  ├─rl-root 17.5G xfs
  └─rl-swap    1G swap
sdb            2G 
├─sdb1         2G zfs_member
└─sdb9         8M 
sdc            2G 
├─sdc1         2G zfs_member
└─sdc9         8M 
sr0         58.4M iso9660

 

6. blockdev command

We can use blockdev command to print a report for the specified device. It is possible to give multiple devices. If none is given, all devices which appear in /proc/partitions are shown. Note that the partition StartSec is in 512-byte sectors.

Check disk space in Linux using 10 different CMDs

You can also use following commands:

# returns size in bytes.
# blockdev --getsize64 /dev/sda

# returns size in 512-byte sectors.
# blockdev --getsz /dev/sda

 

7. lshw command

lshw is a small tool to extract detailed information on the hardware configuration of the machine. It can report exact memory configuration, firmware version, mainboard configuration, CPU version and speed, cache configuration, bus speed, etc. on DMI-capable x86 or IA-64 systems and on some PowerPC machines.

By default lshw will give you a huge output, we can limit that by only printing the information for a specified class such as "disk". To get the list of attached disks and their details such as size we will use lshw -c disk which can also be used to check disk space in Linux.

Here is an output snippet from my Linux node:

Check disk space in Linux using 10 different CMDs

We can further improve the output using lshw with grep:

~]# lshw -c disk | grep -E "logical name|size:"
       logical name: /dev/sda
       size: 15GiB (16GB)
       logical name: /dev/sdb
       size: 8GiB (8589MB)

 

8. Checking disk size from the system logs

We can also use system logs such as boot logs using dmesg or journalctl -b and try to search for respective disk to get more information. The catch is that you should know the disk name unlike other methods which we discussed where we were able to check size of all the available disks without prior knowledge of disk name.

For example, here I am searching for all instance of sda disk in boot logs using dmesg:

Check disk space in Linux using 10 different CMDs

Similarly we can search for any other disk, such as sdb:

 ~]# dmesg | grep sdb
[    3.230296] sd 3:0:0:0: [sdb] 16777216 512-byte logical blocks: (8.59 GB/8.00 GiB)
[    3.230304] sd 3:0:0:0: [sdb] Write Protect is off
[    3.230306] sd 3:0:0:0: [sdb] Mode Sense: 00 3a 00 00
[    3.230316] sd 3:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[    3.238804]  sdb: sdb1
[    3.239698] sd 3:0:0:0: [sdb] Attached SCSI disk

You may also try grepping blocks in dmesg output which can list the available disk with their size:

 ~]# dmesg | grep blocks
[    3.228462] sd 2:0:0:0: [sda] 31457280 512-byte logical blocks: (16.1 GB/15.0 GiB)
[    3.230296] sd 3:0:0:0: [sdb] 16777216 512-byte logical blocks: (8.59 GB/8.00 GiB)

 

9. lsscsi command

lsscsi uses information in sysfs (Linux kernel series 2.6 and later) to list SCSI devices (or hosts) currently attached to the system. Many non-SCSI storage devices (but not all) used the SCSI subsystem in Linux. In lsscsi version 0.30 support was added to list NVMe devices.

We can use lsscsi --size to list all the connected storage devices along with their size as shown below:

~]# lsscsi --size
[0:0:0:0]    cd/dvd  VBOX     CD-ROM           1.0   /dev/sr0        -
[1:0:0:0]    cd/dvd  VBOX     CD-ROM           1.0   /dev/sr1        -
[2:0:0:0]    disk    ATA      VBOX HARDDISK    1.0   /dev/sda   16.1GB
[3:0:0:0]    disk    ATA      VBOX HARDDISK    1.0   /dev/sdb   8.58GB

 

10. sfdisk command

sfdisk is again an alternative to fdisk and parted utility. One of the major difference between fdisk and sfdisk is that sfdisk reads and writes partition tables, but is not interactive like fdisk or cfdisk (it reads input from a file or stdin). It's generally used for partitioning drives from scripts or for partition table backup and recovery.

But it can also be used to check the disk size using sfdisk -l, sample output:

Check disk space in Linux using 10 different CMDs

 

Summary

In Linux, there are several ways to check the available disk space in the system. One way is to use the "df" command, which shows the disk space usage of file systems on the system. Running "df -h" in the terminal will display the total hard disk space available, along with the available and used disk space for each file system.

To check disk space usage by folder in Ubuntu, the "du" command can be used. By default, "du" displays the disk space used by each directory and its subdirectories. Running "du -sh /path/to/folder" will display the total size of the folder in a human-readable format.

In order to check the disk space in a terminal, you can use any of these commands mentioned above, as all of them display the available disk space. Using the "df" command will show the total space available for all file systems mounted on the system, whereas the "du" command can be used to see the disk space usage of a particular folder.

Overall, monitoring disk space usage is important to ensure that you have sufficient storage available for your system and applications to operate efficiently. By using commands like "df" and "du", you can easily check the disk space usage of your system and make informed decisions about managing your storage resources.

 

Deepak Prasad

He is the founder of GoLinuxCloud and brings over a decade of expertise in Linux, Python, Go, Laravel, DevOps, Kubernetes, Git, Shell scripting, OpenShift, AWS, Networking, and Security. With extensive experience, he excels in various domains, from development to DevOps, Networking, and Security, ensuring robust and efficient solutions for diverse projects. You can reach out to him on his LinkedIn profile or join on Facebook page.

Can't find what you're searching for? Let us assist you.

Enter your query below, and we'll provide instant results tailored to your needs.

If my articles on GoLinuxCloud has helped you, kindly consider buying me a coffee as a token of appreciation.

Buy GoLinuxCloud a Coffee

For any other feedbacks or questions you can send mail to admin@golinuxcloud.com

Thank You for your support!!

Leave a Comment