free disk space
utility displays statistics about the amount
of free disk space on the specified
or on the file system of which
is a part. By default, values are
displayed as 512-byte block counts. If no operands are specified, statistics
for all mounted file systems are displayed (subject to the
The options are as follows:
- "Human-readable" output. Use unit suffixes: Byte,
Kilobyte, Megabyte, Gigabyte, Terabyte, Petabyte, Exabyte in order to
reduce the number of digits to four or less. This option is incompatible
with the -P option.
- Include statistics on the number of free inodes. This
option is incompatible with the -P
- By default, all sizes are reported in 512-byte block
counts. The -k option causes the numbers to
be reported in kilobyte counts.
- Display statistics only about mounted file systems with the
MNT_LOCAL flag set. If a non-local file
system is given as an argument, a warning is issued and no information is
given on that file system.
- Print out the previously obtained statistics from the file
systems. This option should be used if it is possible that one or more
file systems are in a state such that they will not be able to provide
statistics without a long delay. When this option is specified,
df will not request new statistics from the
file systems, but will respond with the possibly stale statistics that
were previously obtained.
- Print out information in a stricter format designed to be
parsed by portable scripts.
- Indicate the actions should only be taken on file systems
of the specified type. More than one type
may be specified in a comma-separated list. The list of file system types
can be prefixed with “no” to specify the file system types
for which action should not be taken. If a
file system is given on the command line that is not of the specified
type, a warning is issued and no information is given on that file
It is not an error to specify more than one of the mutually exclusive options
more than one of these options is specified, the last option given overrides
- If the environment variable
BLOCKSIZE is set, and the
-h or -k options
are not specified, the block counts will be displayed in units of that
utility exits 0 on success,
and >0 if an error occurs.
Output, in a strict format suitable for portable scripts, disk space statistics
for the /usr
file system using kilobyte block
$ df -kP /usr
utility is compliant with the
IEEE Std 1003.1-2008
The flags [-hiln
], as well
environment variable, are
extensions to that specification.
This implementation provides the traditional BSD
behaviour, which differs from the X/Open
System Interfaces option specification.
utility appeared in
Version 3 AT&T UNIX