man : df
File: fileutils.info, Node: df invocation, Next: du invocation, Up: Disk usage
`df': Report filesystem disk space usage
`df' reports the amount of disk space used and available on
df [OPTION]... [FILE]...
With no arguments, `df' reports the space used and available on all
currently mounted filesystems (of all types). Otherwise, `df' reports
on the filesystem containing each argument FILE.
Normally the disk space is printed in units of 1024 bytes, but this
can be overridden (*note Block size::).
If an argument FILE is a disk device file containing a mounted
filesystem, `df' shows the space available on that filesystem rather
than on the filesystem containing the device node (i.e., the root
filesystem). GNU `df' does not attempt to determine the disk usage on
unmounted filesystems, because on most kinds of systems doing so
requires extremely nonportable intimate knowledge of filesystem
The program accepts the following options. Also see *Note Common
Include in the listing filesystems that have a size of 0 blocks,
which are omitted by default. Such filesystems are typically
special-purpose pseudo-filesystems, such as automounter entries.
Also, filesystems of type "ignore" or "auto", supported by some
operating systems, are only included if this option is specified.
Append a size letter such as `M' for megabytes to each size.
Powers of 1024 are used, not 1000; `M' stands for 1,048,576 bytes.
Use the `-H' or `--si' option if you prefer powers of 1000.
Append a size letter such as `M' for megabytes to each size. (SI
is the International System of Units, which defines these letters
as prefixes.) Powers of 1000 are used, not 1024; `M' stands for
1,000,000 bytes. Use the `-h' or `--human-readable' option if you
prefer powers of 1024.
List inode usage information instead of block usage. An inode
(short for index node) contains information about a file such as
its owner, permissions, timestamps, and location on the disk.
Print sizes in 1024-byte blocks, overriding the default block size
(*note Block size::).
Limit the listing to local filesystems. By default, remote
filesystems are also listed.
Print sizes in megabyte (that is, 1,048,576-byte) blocks.
Do not invoke the `sync' system call before getting any usage data.
This may make `df' run significantly faster on systems with many
disks, but on some systems (notably SunOS) the results may be
slightly out of date. This is the default.
Use the POSIX output format. This is like the default format
except for the following:
1. The information about each filesystem is always printed on
exactly one line; a mount device is never put on a line by
itself. This means that if the mount device name is more
than 20 characters long (e.g., for some network mounts), the
columns are misaligned.
2. Non-integer values are rounded up, instead of being rounded
down or rounded to the nearest integer.
3. The labels in the header output line are changed to conform
Invoke the `sync' system call before getting any usage data. On
some systems (notably SunOS), doing this yields more up to date
results, but in general this option makes `df' much slower,
especially when there are many or very busy filesystems.
Limit the listing to filesystems of type FSTYPE. Multiple
filesystem types can be specified by giving multiple `-t' options.
By default, nothing is omitted.
Print each filesystem's type. The types printed here are the same
ones you can include or exclude with `-t' and `-x'. The particular
types printed are whatever is supported by the system. Here are
some of the common names (this list is certainly not exhaustive):
An NFS filesystem, i.e., one mounted over a network from
another machine. This is the one type name which seems to be
used uniformly by all systems.
`4.2, ufs, efs...'
A filesystem on a locally-mounted hard disk. (The system
might even support more than one type here; Linux does.)
A filesystem on a CD-ROM drive. HP-UX uses `cdfs', most other
systems use `hsfs' (`hs' for "High Sierra").
An MS-DOS filesystem, usually on a diskette.
Limit the listing to filesystems not of type FSTYPE. Multiple
filesystem types can be eliminated by giving multiple `-x'
options. By default, no filesystem types are omitted.
Ignored; for compatibility with System V versions of `df'.