mount.8

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)mount.8	7.1	4/26/90
.TH mount 8
.SH Name
mount, umount \- mount or unmount file systems
.SH Syntax
\fB/etc/mount\fR [ \fIoptions\fR ] [ \fIdevice\fR ] [ \fIdirectory\fR ]
.PP
\fB/etc/umount\fR [ \fIoptions\fR ] [ \fIdevice\fR ] [ \fIdirectory\fR ]
.SH Description
.NXR "mount command (general)"
.NXR "umount command (general)"
.NXA "mount command (general)" "mount command (NFS)"
.NXA "mount command (general)" "ufs_mount command"
.NXAM "mount command (general)" "fstab file"
.NXR "file system" "mounting"
.NXA "file system" "NFS file system"
.NXA "file system" "UFS file system"
This is a general description of the 
.PN mount 
command.
Additional 
.PN mount 
descriptions are provided to 
define the 
.PN mount
syntax and options for the NFS and UFS file systems.
.PP
Each invocation of the
.PN mount
command announces to the system that a file system
is present on the device \fIdevice\fR.
The file system may be local or remote.
File \fIdirectory\fR
must exist as a directory file.
It becomes the name of the newly mounted file system root.
.PP
If invoked without arguments,
.PN mount
prints the list of mounted file systems.
.PP
Physically write-protected disks and magnetic tape file
systems must be mounted read-only
or an error will occur at mount time.
.PP
General users can only mount file systems with certain restrictions.
For example, the user,
other than the superuser,
performing the mount must own the directory \fIdirectory\fR.
Furthermore, no users other than the superuser can execute
.PN setuid
or
.PN setgid
programs on the mounted file systems.
In addition, users other than the superuser cannot access block or special
character devices such as
.PN rra0g
on the mounted file systems.
.PP
The 
.PN umount
command announces to the system that the removable
file system previously mounted on the specified directory
is to be removed.
Only the person who mounted a particular file system or the
superuser can unmount the file system again.
.SH Options
.TP 12
.B \-a
Reads the file
.PN /etc/fstab
and mounts, or unmounts, all file systems listed there.
.TP 12
.B \-f
Fast unmount.
The
.PN \-f
option has no meaning for local file systems and directories.
However,
for remote file system types (such as NFS), the
.PN \-f
option causes the client to unmount the remotely mounted file systems
and directories without notifying the server.
This can avoid the delay of waiting for acknowledgment
from a server that is down.
.TP 12
\fB\-o\fR \fIoptions\fR
Specifies
a string that is passed to the kernel and used by
the specific file system's mount routine in the kernel.
For specific options,
refer to the file system-specific 
.PN mount 
description, such as 
.MS mount 8nfs .
.TP 12
.B \-r
Indicates that the file system
is to be mounted read only. To share a disk, each host must mount 
the file system with the 
.B \-r
option. 
.TP 12
\fB\-t\fR \fItype\fR
Specifies the type of file system is being mounted.
When used with the 
.PN \-a
option, the
.PN \-t
option mounts all file systems of the given type found in
the
.PN /etc/fstab
file.
For specific file system types,
refer to the file system-specific
.PN mount
description,
such as 
.MS mount 8nfs .
.TP 12
.B \-v
Tells what did or did not happen.
(Verbose flag)
.PP
The options for
.PN umount
are:
.TP 12
.B \-a
Unmounts all mounted file systems.
It may be necessary to execute
.PN umount
.PN \-a
twice to 
accomplish unmounting of all mounted file systems.
.TP 12
.B \-v
Tells what did or did not happen.
(Verbose flag)
.SH Restrictions
.NXR "mount command (general)" "restricted"
Mounting corrupted file systems will crash the system.
.SH Files
.TP 15
.PN /etc/fstab
File systems information table
.SH See Also
getmnt(2), mount(2), fstab(5), fsck(8), mount(8nfs), mount(8ufs)