There are several Linux tools available on the internet to check disk space utilization; we can use any of them. But, Linux has a best built-in command-line utility called “df”. The “df” is the short form of “disk filesystem”, we can get detailed information on used and available disk space on any Linux Operating System.
There are various option we can use with the “df” utility to get the information in a different format. For example, you can get the disk information in a human-readable format by using the “-h” option or parameter with “df” command, it will give you information in bytes, megabytes, and gigabytes.
Here in this article, we will explain various use-cases of ‘df” utility, which can help us to understand it with a practical scenario and real examples.
Examples:
We will discuss the “df” command useability by some of the examples which are using in daily jobs.
The “df” command is in the category of utilities which we are using on daily job, and it helps a lot for Linux Administrator or Engineers.
Checking File System Disk Space Usage
When we execute the “df” command simply without any parameter it gives the information for Filesystem device name, a total number of blocks, Used disk space, available disk space and the filesystem mount point.
# dfFilesystem 1K-blocks Used Available Use% Mounted on
udev 65996684 0 65996684 0% /dev
tmpfs 13203392 1319792 11883600 10% /run
/dev/sda1 824580576 736514880 46156348 95% /
tmpfs 66016960 0 66016960 0% /dev/shm
tmpfs 5120 0 5120 0% /run/lock
tmpfs 66016960 0 66016960 0% /sys/fs/cgroup
tmpfs 13203392 0 13203392 0% /run/user/1000Display all File System Disk Space Usage
Use “-a” parameter with “df” command to print information of all available filesystem’s disk space and utilization.
# df -aFilesystem 1K-blocks Used Available Use% Mounted on
sysfs 0 0 0 - /sys
proc 0 0 0 - /proc
udev 65996684 0 65996684 0% /dev
devpts 0 0 0 - /dev/pts
tmpfs 13203392 1319792 11883600 10% /run
/dev/sda1 824580576 736544180 46127048 95% /
securityfs 0 0 0 - /sys/kernel/security
tmpfs 66016960 0 66016960 0% /dev/shm
tmpfs 5120 0 5120 0% /run/lock
tmpfs 66016960 0 66016960 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/net_cls,net_prio
systemd-1 - - - - /proc/sys/fs/binfmt_misc
mqueue 0 0 0 - /dev/mqueue
hugetlbfs 0 0 0 - /dev/hugepages
debugfs 0 0 0 - /sys/kernel/debug
fusectl 0 0 0 - /sys/fs/fuse/connections
lxcfs 0 0 0 - /var/lib/lxcfs
/dev/sda1 824580576 736544180 46127048 95% /var/lib/docker/aufsDisplay Filesystem Usage in Human Readable Format
In the above command, we get the information about disk usages but not able to identify quickly for us. If this information display in the readable format like Bytes, Megabytes, Gigabytes, etc., it will easy for us to understand.
So, we are using the “-h” parameter with the “df” command to get data in a human-readable format.
# df -hFilesystem Size Used Avail Use% Mounted on
udev 63G 0 63G 0% /dev
tmpfs 13G 1.3G 12G 11% /run
/dev/sda1 787G 703G 44G 95% /
tmpfs 63G 0 63G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 63G 0 63G 0% /sys/fs/cgroup
tmpfs 13G 0 13G 0% /run/user/1000Display File System Information in Bytes
We can also use the “df” command to show the information of File system in Bytes representation of size (1024-bytes block), use the “-k” parameter to get the size in Bytes.
# df -kFilesystem 1K-blocks Used Available Use% Mounted on
udev 65996684 0 65996684 0% /dev
tmpfs 13203392 1327984 11875408 11% /run
/dev/sda1 824580576 736817580 45853648 95% /
tmpfs 66016960 0 66016960 0% /dev/shm
tmpfs 5120 0 5120 0% /run/lock
tmpfs 66016960 0 66016960 0% /sys/fs/cgroup
tmpfs 13203392 0 13203392 0% /run/user/1000Display Information of ‘/’ File System
We can display information of the file system for only ‘/’ device by using the following command:
# df -hT /Filesystem Type Size Used Avail Use% Mounted on
/dev/sda1 ext4 787G 703G 44G 95% /Display File System Information in MegaBytes
We can also use the “df” command to show the information of File system in Megabytes representation of size, use the “-m” parameter to get the size in megabytes.
# df -mFilesystem 1M-blocks Used Available Use% Mounted on
udev 64450 0 64450 0% /dev
tmpfs 12894 1297 11598 11% /run
/dev/sda1 805255 719624 44704 95% /
tmpfs 64470 0 64470 0% /dev/shm
tmpfs 5 0 5 0% /run/lock
tmpfs 64470 0 64470 0% /sys/fs/cgroup
tmpfs 12894 0 12894 0% /run/user/1000Display File System Information in Gigabytes
We can also use the “df” command to show the information of File system in Gigabytes representation of size, use the “-h” parameter to get the size in gigabytes.
# df -hFilesystem Size Used Avail Use% Mounted on
udev 63G 0 63G 0% /dev
tmpfs 13G 1.3G 12G 11% /run
/dev/sda1 787G 703G 44G 95% /
tmpfs 63G 0 63G 0% /dev/shm
tmpfs 63G 0 63G 0% /sys/fs/cgroup
tmpfs 13G 0 13G 0% /run/user/1000Display Inodes uses of File System
To get the information of used inodes in a file system we can use the “-i” parameter with “df” command.
# df -iFilesystem Inodes IUsed IFree IUse% Mounted on
udev 16499171 429 16498742 1% /dev
tmpfs 16504240 641 16503599 1% /run
/dev/sda1 52371456 684303 51687153 2% /
tmpfs 16504240 1 16504239 1% /dev/shm
tmpfs 16504240 3 16504237 1% /run/lock
tmpfs 16504240 16 16504224 1% /sys/fs/cgroup
tmpfs 16504240 4 16504236 1% /run/user/1000Display File System Type
We can also use the “df” command to check the file system type for devices. To check file system type using “df” command use the “-T” parameter, as shown below:
# df -TFilesystem Type 1K-blocks Used Available Use% Mounted on
udev devtmpfs 65996684 0 65996684 0% /dev
tmpfs tmpfs 13203392 1336176 11867216 11% /run
/dev/sda1 ext4 824580576 736962088 45709140 95% /
tmpfs tmpfs 66016960 0 66016960 0% /dev/shm
tmpfs tmpfs 5120 0 5120 0% /run/lock
tmpfs tmpfs 66016960 0 66016960 0% /sys/fs/cgroup
tmpfs tmpfs 13203392 0 13203392 0% /run/user/1000Display Certain File System Type
If we want to display only certain file system type in the “df” command output, we can use the “-t” parameter along with file system type. For example, we can use the following command to display disk uses information for ext4 types of file systems:
# df -t ext4Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 824580576 736987412 45683816 95% /Display without certain File System Type
Similarly, the above example, we can use the “df” command to display file system information with excluding specific file system type. To exclude file system type from “df” output use the “-x” parameter. For example, here we display file system information after excluding “ext4” file system type:
# df -x ext4Filesystem 1K-blocks Used Available Use% Mounted on
udev 65996684 0 65996684 0% /dev
tmpfs 13203392 1336176 11867216 11% /run
tmpfs 66016960 0 66016960 0% /dev/shm
tmpfs 5120 0 5120 0% /run/lock
tmpfs 66016960 0 66016960 0% /sys/fs/cgroup
tmpfs 13203392 0 13203392 0% /run/user/1000df command help
To get more help on the “df” command, use “–help” parameter with the command, as shown below:
# df --helpUsage: df [OPTION]... [FILE]...
Show information about the file system on which each FILE resides,
or all file systems by default.
Mandatory arguments to long options are mandatory for short options too.
-a, --all include pseudo, duplicate, inaccessible file systems
-B, --block-size=SIZE scale sizes by SIZE before printing them; e.g.,
'-BM' prints sizes in units of 1,048,576 bytes;
see SIZE format below
-h, --human-readable print sizes in powers of 1024 (e.g., 1023M)
-H, --si print sizes in powers of 1000 (e.g., 1.1G)
-i, --inodes list inode information instead of block usage
-k like --block-size=1K
-l, --local limit listing to local file systems
--no-sync do not invoke sync before getting usage info (default)
--output[=FIELD_LIST] use the output format defined by FIELD_LIST,
or print all fields if FIELD_LIST is omitted.
-P, --portability use the POSIX output format
--sync invoke sync before getting usage info
--total elide all entries insignificant to available space,
and produce a grand total
-t, --type=TYPE limit listing to file systems of type TYPE
-T, --print-type print file system type
-x, --exclude-type=TYPE limit listing to file systems not of type TYPE
-v (ignored)
--help display this help and exit
--version output version information and exit
Display values are in units of the first available SIZE from --block-size,
and the DF_BLOCK_SIZE, BLOCK_SIZE and BLOCKSIZE environment variables.
Otherwise, units default to 1024 bytes (or 512 if POSIXLY_CORRECT is set).
The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
FIELD_LIST is a comma-separated list of columns to be included. Valid
field names are: 'source', 'fstype', 'itotal', 'iused', 'iavail', 'ipcent',
'size', 'used', 'avail', 'pcent', 'file' and 'target' (see info page).
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
Full documentation at: <http://www.gnu.org/software/coreutils/df>
or available locally via: info '(coreutils) df invocation'Last Word
I have tried to include all primary uses of “df” command in the daily life of System Admin or Engineer. If you feel some of the examples need to in the above list, please let us know using the comment section.
