df.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)df.1	8.2	2/18/91
.TH df 1
.SH Name
df \- display free and used disk space
.SH Syntax
.B df
[\fB\-i\fR] [\fB\-l\fR] [\fB\-n\fR] [\|\fIfilesystem\fR...\|] [\|\fIfile\fR...\|]
.SH Description
.NXA "df command" "dumpfs command"
.NXR "disk" "displaying free space"
.NXR "disk" "displaying used space"
The
.PN df
command displays the amount of disk space
available on the specified
.I file system,
for example,
.PN /dev/ra0a .
It also displays the amount of available disk space
on the file system in which the specified
.I file
is contained,
for example,
.PN $HOME .
If a device is given that has no file systems
mounted on it,
.PN df
displays the information for the root file system.
Without any arguments or options,
.PN df
displays
shows all mounted filesystems, including those manually
mounted without use of the 
.PN /etc/fstab 
file.
The numbers are reported in kilobytes. 
.PP
Unless the
\fB\-n\fR
option is specified,
.PN df
updates the statistics stored in memory for the file system
specified,
before it returns the information.
.SH Options
.IP \fB\-i\fR 5
Also report the number of used and free inodes.
.IP \fB\-l\fR
Reports on locally mounted disks only.
.IP \fB\-n\fR
Do not update the file system statistics stored in memory.
Instead,
return whatever statistics are stored in memory.
This prevents
.PN df
from hanging in the event that a server containing the specified file system
is down.
.SH Restrictions
You cannot use the 
.PN df
command to find free space on an unmounted file system using the
block or character special device name.
Instead,
use the
.PN dumpfs
command.
.SH Examples
.EX 0
% df
Filesystem     Total    kbytes  kbytes   %
node           kbytes   used    free     used    Mounted on
/dev/ra1a       7429    2085    4602     31%    /tmp
/dev/ra0e      30519   14817   12651     54%    /usr/spool
/dev/ra0h     313233  122858  159052     44%    /usr/staff1
.EE
.PP
The total disk space is the total space that was created
during the making of the file system.
The addition of the used space,
the free space and a percentage of reserved space
is the total space.
The default value for the reserved space is 10%.
.SH Files
.TP 12
.PN /etc/fstab
List of mounted file systems
.SH See Also
getmnt(2), fstab(5), dumpfs(8), icheck(8), mkfs(8), newfs(8), quot(8)