.\"	$OpenBSD: df.1,v 1.47 2014/03/17 21:32:12 jmc Exp $
.\"	$NetBSD: df.1,v 1.12 1995/12/05 02:42:45 jtc Exp $
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.\"	@(#)df.1	8.2 (Berkeley) 1/13/92
.\"
.Dd $Mdocdate: March 17 2014 $
.Dt DF 1
.Os
.Sh NAME
.Nm df
.Nd display free disk space
.Sh SYNOPSIS
.Nm df
.Op Fl hiklnP
.Op Fl t Ar type
.Oo
.Op Ar file | file_system
.Ar ...
.Oc
.Sh DESCRIPTION
The
.Nm
utility displays statistics about the amount of free disk space on the
specified
.Ar file_system
or on the file system of which
.Ar file
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
.Fl l
and
.Fl t
options, below).
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl h
"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
.Fl P
option.
.It Fl i
Include statistics on the number of free inodes.
This option is incompatible with the
.Fl P
option.
.It Fl k
By default, all sizes are reported in 512-byte block counts.
The
.Fl k
option causes the numbers to be reported in kilobyte counts.
.It Fl l
Display statistics only about mounted file systems with the
.Dv 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.
.It Fl n
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,
.Nm
will not request new statistics from the file systems, but will respond
with the possibly stale statistics that were previously obtained.
.It Fl P
Print out information in a stricter format designed to be parsed
by portable scripts.
.It Fl t Ar type
Indicate the actions should only be taken on
file systems of the specified
.Ar type .
More than one type may be specified in a comma-separated list.
The list of file system types can be prefixed with
.Dq no
to specify the file system types for which action should
.Em 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 system.
.El
.Pp
It is not an error to specify more than one of
the mutually exclusive options
.Fl h
and
.Fl k .
Where more than one of these options is specified,
the last option given overrides the others.
.Sh ENVIRONMENT
.Bl -tag -width BLOCKSIZE
.It Ev BLOCKSIZE
If the environment variable
.Ev BLOCKSIZE
is set, and the
.Fl h
or
.Fl k
options are not specified, the block counts will be displayed in units of that
size block.
.El
.Sh EXIT STATUS
.Ex -std df
.Sh EXAMPLES
Output, in a strict format suitable for portable scripts, disk space
statistics for the
.Pa /usr
file system using kilobyte block sizes:
.Pp
.Dl $ df -kP /usr
.Sh SEE ALSO
.Xr quota 1 ,
.Xr getfsstat 2 ,
.Xr statfs 2 ,
.Xr getmntinfo 3 ,
.Xr fstab 5 ,
.Xr mount 8 ,
.Xr quot 8
.Sh STANDARDS
The
.Nm
utility is compliant with the
.St -p1003.1-2008
specification.
.Pp
The flags
.Op Fl hiln ,
as well as the
.Ev BLOCKSIZE
environment variable,
are extensions to that specification.
.Pp
This implementation provides the traditional
.Bx
.Fl t
behaviour,
which differs from the
X/Open System Interfaces option
specification.
.Sh HISTORY
A
.Nm
utility appeared in
.At v3 .