Linux df Command

Linux Command Manual

The Linux df (disk free) command is used to display statistics on disk usage of file systems on a Linux system.

Syntax

df [options]... [FILE]...

-a, --all Include all file systems with 0 Blocks
--block-size={SIZE} Use Blocks of size {SIZE}
-h, --human-readable Display sizes in human-readable format (default is without this option)
-H, --si Similar to -h, but uses 1000 as the unit instead of 1024
-i, --inodes List inode information instead of used blocks
-k, --kilobytes Equivalent to --block-size=1024
-l, --local Limit listing to local file systems
-m, --megabytes Equivalent to --block-size=1048576
--no-sync Do not sync before getting information (default)
-P, --portability Use POSIX output format
--sync Sync before getting information
-t, --type=TYPE Limit listing to file systems of type TYPE
-T, --print-type Display type of file system
-x, --exclude-type=TYPE Exclude file systems of type TYPE
-v (ignored)
--help Display help information and exit
--version Output version information and exit

Example

Display disk usage statistics of file systems:

# df
Filesystem     1K-blocks    Used     Available Use% Mounted on
/dev/sda6       29640780 4320704     23814388  16%     /
udev             1536756       4     1536752    1%     /dev
tmpfs             617620     888     616732     1%     /run
none                5120       0     5120       0%     /run/lock
none             1544044     156     1543888    1%     /run/shm

The first column specifies the file system name, the second column specifies the total memory in 1K blocks (1024 bytes each). The Used and Available columns specify the amount of memory in use and available, respectively.

The Use% column specifies the percentage of memory in use, and the last column "Mounted on" specifies the mount point of the file system.

df can also display disk usage information for a specific file system:

# df test
Filesystem     1K-blocks    Used      Available Use% Mounted on
/dev/sda6       29640780    4320600   23814492  16%       /

The output of the df command with the -i option displays inode information instead of block usage:

df -i
Filesystem      Inodes    IUsed    IFree     IUse% Mounted on
/dev/sda6      1884160    261964   1622196   14%        /
udev           212748     560      212188    1%         /dev
tmpfs          216392     477      215915    1%         /run
none           216392     3        216389    1%         /run/lock
none           216392     8        216384    1%         /run/shm

Display all information:

# df --total
Filesystem     1K-blocks    Used    Available Use% Mounted on
/dev/sda6       29640780 4320720    23814372  16%     /
udev             1536756       4    1536752   1%      /dev
tmpfs             617620     892    616728    1%      /run 
none                5120       0    5120      0%      /run/lock 
none             1544044     156    1543888   1%      /run/shm 
total           33344320 4321772    27516860  14%

We see at the end of the output, an additional line is included, showing the totals for each column.

The -h option, which can be used to produce human-readable format of the df command's output:

df -h

Filesystem Size Used Avail Use% Mounted on /dev/sda6 29G 4.2G 23G 16% / udev 1.5G 4.0K 1.5G 1% /dev tmpfs 604M 892K 603M 1% /run none 5.0M 0 5.0M 0% /run/lock none 1.5G 156K 1.5G 1% /run/shm ```

We can see that the output displays numbers in the form of 'G' (gigabytes), "M" (megabytes), and "K" (kilobytes).

This makes the output easier to read and understand, thus making the display readable. Note that the name of the second column has also changed to "Size" for readability.

Linux Command Manual

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