freebsd-skq/bin/df/df.1
julian 88e6664e72 Most modern OSs have the ability to flag certain mounts as ones to
be ignored by default by the df(1) program.  This is used mostly to
avoid stat()-ing entries that do not represent "real" disk mount
points (such as those made by an automounter such as amd.)  It is
also useful not to have to stat() these entries because it takes
longer to report them that for other file systems, being that these
mount points are served by a user-level file server and resulting in
several context switches.  Worse, if the automounter is down
unexpectedly, a causal df(1) will hang in an interruptible way.

PR:		kern/9764
Submitted by:	Erez Zadok <ezk@cs.columbia.edu>
1999-11-01 04:57:43 +00:00

133 lines
4.1 KiB
Groff

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.\" @(#)df.1 8.3 (Berkeley) 5/8/95
.\" $FreeBSD$
.\"
.Dd May 8, 1995
.Dt DF 1
.Os BSD 4
.Sh NAME
.Nm df
.Nd display free disk space
.Sh SYNOPSIS
.Nm df
.Op Fl aikn
.Op Fl t Ar type
.Op Ar file | Ar filesystem ...
.Sh DESCRIPTION
.Nm Df
displays statistics about the amount of free disk space on the specified
.Ar filesystem
or on the filesystem of which
.Ar file
is a part.
Values are displayed in 512-byte per block counts.
If neither a file or a filesystem operand is specified,
statistics for all mounted filesystems are displayed
(subject to the
.Fl t
option below).
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl a
Show all mount points, including those that were mounted with the MNT_IGNORE
flag.
.It Fl i
Include statistics on the number of free inodes.
.It Fl k
Use 1024-byte (1-Kbyte) blocks rather than the default. Note that
this overrides the
.Ev BLOCKSIZE
specification from the environment.
.It Fl n
Print out the previously obtained statistics from the filesystems.
This option should be used if it is possible that one or more
filesystems 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 filesystems, but will respond
with the possibly stale statistics that were previously obtained.
.It Fl t
Only print out statistics for filesystems of the specified types.
More than one type may be specified in a comma separated list.
The list of filesystem types can be prefixed with
.Dq no
to specify the filesystem types for which action should
.Em not
be taken.
For example, the
.Nm
command:
.Bd -literal -offset indent
df -t nonfs,mfs
.Ed
.Pp
lists all filesystems except those of type
.Tn NFS
and
.Tn MFS .
The
.Xr lsvfs 1
command can be used to find out the types of filesystems
that are available on the system.
.El
.Sh ENVIRONMENT
.Bl -tag -width BLOCKSIZE
.It Ev BLOCKSIZE
If the environment variable
.Ev BLOCKSIZE
is set, the block counts will be displayed in units of that size block.
.El
.Sh BUGS
The
.Fl n
and
.Fl t
flags are ignored if a file or filesystem is specified.
.Sh SEE ALSO
.Xr lsvfs 1 ,
.Xr quota 1 ,
.Xr fstatfs 2 ,
.Xr getfsstat 2 ,
.Xr statfs 2 ,
.Xr getmntinfo 3 ,
.Xr fstab 5 ,
.Xr mount 8 ,
.Xr quot 8
.Sh HISTORY
A
.Nm
command appeared in
.At v1 .