I recently switched from a Windows server to a Linux server operating system and need Linux check disk space command. I am using Ubuntu LTS 16.04 and CentOS 7.x server. How do I find out disk space utilization information using command line option?

Linux offer the following commands to check disk space usage:

Linux command to check disk space using:

df command – Shows the amount of disk space used and available on Linux file systems.

du command – Display the amount of disk space used by the specified files and for each subdirectory.

btrfs fi df /device/ – Show disk space usage information for a btrfs based mount point/file system.

Linux check disk space with df command

Open the terminal and type the following command to check disk space.

The basic syntax for df is:

df [options] [devices]

Type:

df

df -H

Sample outputs:

Fig.01: linux check disk space with df command

Fig.01: df command in action

The items in square brackets are optional. You can simply type the df command (i.e. no arguments), to see a table that lists for each device name on the system.

See information about specific filesystem

You can give a device or mount point as an argument, and df report data only for the filesystem physically residing on that device. For example, the following command provides information only for the partition /dev/sda:

$ df /dev/sda

$ df -h /dev/sdc1

$ df /data/

Sample outputs:

Filesystem 1K-blocks Used Available Use% Mounted on

/dev/sda 2930266584 69405248 2859579472 3% /data

UNDERSTANDING DF COMMAND OUTPUT

The valid fields are as follows:

Display name Valid field name (for --output option) Description

Filesystem source The source of the mount point, usually a device.

1K-blocks size Total number of blocks.

Used used Number of used blocks.

Available avail Number of available blocks.

Use% pcent Percentage of USED divided by SIZE.

Mounted on target The mount point.

You can pass the output format defined by ‘valid field name’ as follows:

$ df --output=field1,field2,...

$ df --output=source,used,avail /data/

Sample outputs:

Filesystem Used Avail

/dev/md0 5.4G 115G

udev 0 11M

tmpfs 6.2M 414M

tmpfs 4.1k 1.1G

tmpfs 4.1k 5.3M

tmpfs 0 1.1G

/dev/md2 818G 688G

tmpfs 0 210M

tmpfs 0 210M

/dev/mapper/cryptvg-mybackup 77G 526G

You can print all available fields, enter:

$ df --o

Sample outputs:

Filesystem Type Inodes IUsed IFree IUse% 1K-blocks Used Avail Use% File Mounted on

udev devtmpfs 379248 333 378915 1% 10240 0 10240 0% - /dev

tmpfs tmpfs 381554 498 381056 1% 610488 9704 600784 2% - /run

/dev/sdc1 ext3 956592 224532 732060 24% 14932444 7836056 6331204 56% - /

tmpfs tmpfs 381554 1 381553 1% 1526216 0 1526216 0% - /dev/shm

tmpfs tmpfs 381554 4 381550 1% 5120 0 5120 0% - /run/lock

tmpfs tmpfs 381554 14 381540 1% 1526216 0 1526216 0% - /sys/fs/cgroup

/dev/sda btrfs 0 0 0 - 2930266584 69405248 2859579472 3% - /data

tmpfs tmpfs 381554 4 381550 1% 305244 0 305244 0% - /run/user/0

Express df output in human readable form

Pass the -h option to see output in human readable format. You will device size in gigabytes or terabytes or megabytes:

$ df -h ### Human format

$ df -m ### Show output size in one-megabyte

$ df -k ### Show output size in one-kilobyte blocks (default)

Display output using inode usage instead of block usage

An inode is a data structure on a Linux file system that stores all information about file. To list inode information, enter:

$ df -i

$ df -i -h

Sample outputs:

Filesystem Inodes IUsed IFree IUse% Mounted on

udev 371K 333 371K 1% /dev

tmpfs 373K 498 373K 1% /run

/dev/sdc1 935K 220K 715K 24% /

tmpfs 373K 1 373K 1% /dev/shm

tmpfs 373K 4 373K 1% /run/lock

tmpfs 373K 14 373K 1% /sys/fs/cgroup

/dev/sda 0 0 0 - /data

tmpfs 373K 4 373K 1% /run/user/0

Find out the type of each file system displayed

Pass the -T option to display the type of each filesystems listed such as ext4, btrfs, ext2, nfs4, fuse, cgroup, cputset, and more:

$ df -T

$ df -T -h

$ df -T -h /data/

Sample outputs:

Filesystem Type Size Used Avail Use% Mounted on

/dev/sda btrfs 2.8T 67G 2.7T 3% /data

Limit listing to file systems of given type

The syntax is:

$ df -t ext3 #Only see ext3 file system

$ df -t ext4 #Only see ext4 file system

$ df -t btrfs #Only see btrfs file system

Exclude given file system type

To list all but exclude ext2 filesystem pass the -x TYPE option, enter:

$ df -x ext2

Show all file system

Pass the -a or --all option to the df command to include in its output filesystems that have a size of zero blocks, run:

$ df -a

Filesystem 1K-blocks Used Available Use% Mounted on

sysfs 0 0 0 - /sys

proc 0 0 0 - /proc

udev 10240 0 10240 0% /dev

devpts 0 0 0 - /dev/pts

tmpfs 610488 9708 600780 2% /run

/dev/sdc1 14932444 7836084 6331176 56% /

securityfs 0 0 0 - /sys/kernel/security

tmpfs 1526216 0 1526216 0% /dev/shm

tmpfs 5120 0 5120 0% /run/lock

tmpfs 1526216 0 1526216 0% /sys/fs/cgroup

cgroup 0 0 0 - /sys/fs/cgroup/systemd

pstore 0 0 0 - /sys/fs/pstore

cgroup 0 0 0 - /sys/fs/cgroup/cpuset

cgroup 0 0 0 - /sys/fs/cgroup/cpu,cpuacct

cgroup 0 0 0 - /sys/fs/cgroup/blkio

cgroup 0 0 0 - /sys/fs/cgroup/memory

cgroup 0 0 0 - /sys/fs/cgroup/devices

cgroup 0 0 0 - /sys/fs/cgroup/freezer

cgroup 0 0 0 - /sys/fs/cgroup/net_cls,net_prio

cgroup 0 0 0 - /sys/fs/cgroup/perf_event

systemd-1 - - - - /proc/sys/fs/binfmt_misc

fusectl 0 0 0 - /sys/fs/fuse/connections

debugfs 0 0 0 - /sys/kernel/debug

mqueue 0 0 0 - /dev/mqueue

hugetlbfs 0 0 0 - /dev/hugepages

/dev/sda 2930266584 69405248 2859579472 3% /data

rpc_pipefs 0 0 0 - /run/rpc_pipefs

tmpfs 305244 0 305244 0% /run/user/0

binfmt_misc 0 0 0 - /proc/sys/fs/binfmt_misc

These file systems omitted by default.

Getting more help about the df command

Pass the --help option see a brief help message:

$ df --help

Or read its man page by typing the following command:

$ df(1)

Linux check disk space with the du command

The du command is very useful to track down disk space hogs. It is useful to find out the names of directories and files that consume large amounts of space on a disk. The basic syntax is:

du

du /path/do/dir

du [options] [directories and/or files]

To see the names and space consumption of each of the directories including all subdirectories in the directory tree, enter:

$ du

Sample outputs:

16 ./.aptitude

12 ./.ssh

56 ./apcupsd

8 ./.squidview

4 ./kernel.build

12 ./.elinks

8 ./.vim

8 ./.config/htop

12 ./.config

648 .

The first column is expressed in kilobytes (file size) and the second column is the filename or directory name.

See du output in human readable format

Pass the -h option to display size in K (kilobytes), M (megabytes), G (gigabytes) instead of the default kilobytes:

$ du -h

Sample outputs:

16K ./.aptitude

12K ./.ssh

56K ./apcupsd

8.0K ./.squidview

4.0K ./kernel.build

12K ./.elinks

8.0K ./.vim

8.0K ./.config/htop

12K ./.config

648K .

Finding information about any directory trees or files

To find out /etc/ directory space usage, enter:

# du /etc/

# du -h /etc/

The following will report the sizes of the thee files named hdparm, iptunnel and ifconfig that are located in the /sbin directory:

$ du /sbin/hdparm /sbin/iptunnel /sbin/ifconfig

$ du -h /sbin/hdparm /sbin/iptunnel /sbin/ifconfig

Sample outputs:

112K /sbin/hdparm

24K /sbin/iptunnel

72K /sbin/ifconfig

How do I summarize disk usage for given directory name?

Pass the -s option to the du command. In this example, ask du command to report only the total disk space occupied by a directory tree and to suppress subdirectories:

# du -s /etc/

# du -sh /etc/

Sample outputs:

6.3M /etc/

Pass the -a (all) option to see all files, not just directories:

# du -a /etc/

# du -a -h /etc/

Sample outputs:

4.0K /etc/w3m/config

4.0K /etc/w3m/mailcap

12K /etc/w3m

4.0K /etc/ConsoleKit/run-seat.d

4.0K /etc/ConsoleKit/seats.d/00-primary.seat

8.0K /etc/ConsoleKit/seats.d

4.0K /etc/ConsoleKit/run-session.d

20K /etc/ConsoleKit

...

....

..

...

4.0K /etc/ssh/ssh_host_rsa_key

4.0K /etc/ssh/ssh_host_rsa_key.pub

4.0K /etc/ssh/ssh_host_dsa_key

244K /etc/ssh/moduli

4.0K /etc/ssh/sshd_config

272K /etc/ssh

4.0K /etc/python/debian_config

8.0K /etc/python

0 /etc/.pwd.lock

4.0K /etc/ldap/ldap.conf

8.0K /etc/ldap

6.3M /etc/

You can also use star ( * ) wildcard, which will match any character. For example, to see the size of each png file in the current directory, enter:

$ du -ch *.png

52K CIQTK4FUAAAbjDw.png-large.png

68K CX23RezWEAA0QY8.png-large.png

228K CY32cShWkAAaNLD.png-large.png

12K CYaQ3JqU0AA-amA.png-large.png

136K CYywxDfU0AAP2py.png

172K CZBoXO1UsAAw3zR.png-large.png

384K Screen Shot 2016-01-19 at 5.49.21 PM.png

324K TkamEew.png

8.0K VQx6mbH.png

64K fH7rtXE.png

52K ipv6-20-1-640x377.png

392K unrseYB.png

1.8M total

The -c option tells du to display grand total.

Putting it all together

To list top 10 directories eating disk space in /etc/, enter:

# du -a /etc/ | sort -n -r | head -n 10

Sample outputs:

8128 /etc/

928 /etc/ssl

904 /etc/ssl/certs

656 /etc/apache2

544 /etc/apache2/mods-available

484 /etc/init.d

396 /etc/php5

336 /etc/sane.d

308 /etc/X11

268 /etc/ssl/certs/ca-certificates.crt

For more information on the du command, type:

$ man du

$ du --help

Dealing with btrfs file system

For btrfs filesystem use the btrfs fi df command to see space usage information for a mount point. The syntax is:

btrfs filesystem df /path/

btrfs fi df /dev/path

btrfs fi df [options] /path/

Examples

# btrfs fi df /data/

# btrfs fi df -h /data/

Sample outputs:

Data, RAID1: total=71.00GiB, used=63.40GiB

System, RAID1: total=8.00MiB, used=16.00KiB

Metadata, RAID1: total=4.00GiB, used=2.29GiB

GlobalReserve, single: total=512.00MiB, used=0.00B

To see raw numbers in bytes, run:

# btrfs fi df -b /data/

OR

# btrfs fi df -k /data/ ### show sizes in KiB ##

# btrfs fi df -m /data/ ### show sizes in MiB ##

# btrfs fi df -g /data/ ### show sizes in GiB ##

# btrfs fi df -t /data/ ### show sizes in TiB ##

Summary For Linux Check Disk Space Commands

Use du command when you need to estimate file space usage. To report file system disk space usage use the df command. btrfs df must be used when using btrfs file system. Fore more info see GNU coreutils page here.