restore.8

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)restore.8	8.1	9/11/90
.TH restore 8
.SH Name
restore \- incremental file system restore
.SH Syntax
.B /etc/restore
\fIkey\fR [ \fIname\fR... ]
.SH Description
.NXB "restore command"
.NXA "dump command" "restore command"
.NXB "file system" "restoring incremental dumps"
The
.PN restore
command 
reads from magnetic tapes, disks, a file, or a pipe
created by the
.MS dump 8
command.  The default dump media from which files are read is
.PN /dev/rmt0h .  
You can request another dump device or dump image file by using
the 
.B f
key modifier.
The
.I key
is a character string containing one function letter and possibly one 
or more function modifiers.  Other arguments to the command are
file or directory names specifying the files to be restored.
Unless the
.B h
key is specified, the appearance of a directory
name refers to all files and, recursively, the subdirectories
of that directory.
The
function portion of the key
is specified by one of the following letters:
.SH Keys
.NXB "restore command" "keys"
.TP 5 
.B i
This key allows interactive restoration of files from the dump media.
After reading in the directory information from the dump media,
.PN restore
lets the user move
around the directory tree selecting or deselecting
files to be extracted.
The available interactive commands are: 
.RS 5
.TP 12
\fBls \fR[\fIarg\fR]
List the specified directory.  If no directory is specified,
the user's current directory is listed.
Entries that are directories are appended with a slash (/).
Entries that have been marked for extraction are prepended with an 
asterisk (*).
If the 
.B verbose 
key is set,
the inode number of each entry is also listed.
.TP
\fBcd \fIarg\fR
Change the current working directory to the directory specified.
.TP
\fB pwd\fR
Print the full pathname of the current working directory.
.TP
\fBadd\fR [\fIarg\fR] 
The current directory or the specified argument 
(a directory or file)
is added to the extraction list 
(the list of files to be extracted).  
If a directory is specified, then it and all its descendents are
added to the extraction list,
unless the
.B h
key is specified on the command line.
Files that are on the extraction list are prepended with an
asterisk (*)
when they are listed by 
.BR ls .
.TP
\fBdelete\fR [\fIarg\fR]
The current directory or specified argument
is deleted from the extraction list (the list of
files to be extracted).  
If a directory is specified, then it and all its descendents are
deleted from the extraction list,
unless the
.B h
key modifier is specified on the command line.
The easiest way to extract most of the files from a directory 
is to add the directory to the extraction list and then delete
those files that are not needed.
.TP
\fBextract\fR
All the files on the extraction list are extracted
from the dump media.
The
.PN restore
command asks which volume the user wishes to mount.
.TP
\fBverbose\fR
The verbose (
.B v
) key is toggled. 
Entering the command turns on verbose.  Entering the command
again turns off verbose.
When used, the verbose key causes the 
.B ls
command to list the inode numbers of all entries.
It also causes
.PN restore
to print out information about each file as it is extracted.
.TP
\fBhelp\fR
List a summary of the available commands.
.TP
\fBquit\fR
The
.PN restore 
utility immediately exits,
even if the extraction list is not empty.
.RE
.TP 5
.B R
The
.PN restore
utility prompts for a particular volume of a multivolume
set on which to restart a full restore. 
This option lets
.PN restore
be interrupted and then restarted.
.TP 5
.B r
The dump media's data is read into the current directory.
You should use this function key only to restore the complete
dump media onto a newly created file system, or to restore incremental
dump media after a full level-0 restore.  See the Examples section for
a typical sequence to restore complete dump media.
Note that
.PN restore
leaves a file, 
.PN restoresymtab ,
in the root directory to pass information between incremental
restore passes.  Remove this file after the last
incremental dump media has been restored.
A 
.MS dump 8 
followed by a 
.MS newfs 8 
and a 
.MS restore 8 
can be used to change the size of a file system.
.TP 5
.B t
The names of the specified files are listed if they occur
on the dump media.  If no 
.I name
argument is given, then the
root directory is listed.  This results in the entire contents
of the dump media being listed, unless the
.B h
key modifier has been specified.
.TP 5
.B x
The files specified by the
.I name
argument are extracted from the dump media.  If a named
file matches a directory whose contents had been written onto
the dump media and the
.B h
key modifier is not specified, the directory is recursively
extracted.  The owner, modification time, and mode are
restored, if possible.
If no
.I name
argument is given, the root directory is extracted.  This
results in the extraction of the
entire contents of the dump media unless
the
.B h
key modifier has been specified.
.PP
You can use any of the following characters in addition to the 
letter that selects the function desired: 
.TP 5
.B B
The next argument to
.PN restore
is a number giving the size, in 1024-byte blocks, of a
fixed-size storage medium, such as diskettes or removable
disks (see the Examples section). 
The
.PN restore
command does not ask whether it should abort the restore
if there is a dump media read error.  It always tries to
skip over the bad block(s) and continue.
.TP 5
.B f
The next argument to
.PN restore
is used as the name of the archive instead of 
.PN /dev/rmt0h .
If the argument is a dash (\fB\-\fR),
.PN restore
reads from standard input (see the Examples section).
.TP 5
.B h
The
.PN restore
command extracts the actual directory, rather than the files
that it references.  This prevents hierarchical restoration of
complete subtrees from the dump media:
.TP 5
.B m
The
.PN restore
command extracts by inode numbers rather than by file name.  This
is useful if only a few files are being extracted, and you want
to avoid typing the complete pathname to the file.
.TP 5
.B s
The next argument
identifies
which dump file on the dump media is to be used by 
.PN restore .
This is useful when
the dump media has more than one dump image on it and  
not all of them will be restored.
.TP 5
.B v
Normally,
.PN restore
does its work silently.
The
.B v
(verbose)
key modifier causes it to display
the name of each file it treats,
preceded by its file type.
.NXE "restore command" "keys"
.SH Examples
.NXR "restore command" "examples"
The following example shows a typical sequence of
commands to restore complete dump media.
.EX
/etc/newfs /dev/rra0g ra60
/etc/mount /dev/ra0g /mnt
cd /mnt
restore r
.EE
Another
.PN restore
can be done to get an incremental dump.
.PP
The following example shows how
.MS dump 8
and
.MS restore 8
can be used in a pipeline to dump and restore a file system:
.EX
dump 0f - /usr | (cd /mnt; restore xf -)
.EE
The following example shows how to restore files interactively
from a dump on RX50 diskettes:
.EX
restore iBf 400 /dev/ra2a
.EE
.SH Restrictions
.NXR "restore command" "restricted"
The
.PN restore
utility
can make errors when doing incremental restores from
dump media that were made on active file systems.
.PP
You must do a level 0 dump after a full restore.
Because 
.PN restore 
runs in user code,
it has no control over inode allocation;
thus, you must do a full 
.PN restore 
to get a new set of directories
that reflects the new inode numbering,
even though the contents of the files are unchanged.
.SH Diagnostics
.NXB "restore command" "diagnostics"
Complains about bad key characters.
.PP
Complains if it gets a dump media read error.
If 
the user responds with a y,
.PN restore
attempts to continue the restore.
.PP
If the dump extends over more than one dump volume,
.PN restore
will ask the user to change volumes.
If the
.B x
or
.B i
function key has been specified,
.PN restore
also asks which volume the user wishes to mount.
.PP
There are numerous consistency checks that can be listed by
.PN restore .
Most checks are self-explanatory. 
Some common errors are: 
.PP
.B "Converting to new file system format"
.br
If dump media created from the Fast File System (FFS)
has been loaded.
It is automatically converted to the Berkeley Version 4.2
file system format.
.PP
.B "<\fIfilename\fP>: not found on tape{disk}"
.br
The specified file name was listed in the dump media directory,
but was not found on the media.
This is caused by dump media read errors while looking for the file
or from using dump media created on an active file system.
.B "Expected next file <\fIinumber\fP>, got <\fIinumber\fP>"
.br
A file that was not listed in the directory was found on the media.
This can occur when using dump media created on an active file system.
.PP
.B "Incremental tape{disk} too low"
.br
When doing incremental restore,
dump media was loaded that was written 
before the previous incremental media
or has too low an incremental level.  
.PP 
.B "Incremental tape{disk} too high" 
.br
When doing incremental restore,
dump media that does not begin its 
coverage where the previous incremental 
dump media left off,
or that has too high an incremental level has been loaded.
.PP 
.B "Tape{Disk} read error while restoring <\fIfilename\fP>"
.br
.B "Dump media read error while skipping over inode <\fIinumber\fP>"
.br
.B "Dump media read error while trying to resynchronize"
.br
A dump media read error has occurred.
If a file name is specified,
then its contents are probably partially wrong.
If an inode is being skipped or the restore is trying to resynchronize,
then no extracted files have been corrupted,
although files may not be found on the dump media.
.PP 
.B "resync restore, skipped <num> blocks"
.br
After a dump media read error, 
.PN restore
may have to resynchronize itself.
This message lists the number of blocks that were skipped. 
.NXE "restore command" "diagnostics"
.SH Files
.TP 15
.PN /dev/rmt0h
Default tape drive
.TP
.PN /tmp/rstdir
File containing directories on the dump media
.TP
.PN /tmp/rstmode*
Owner, mode, and time stamps for directories
.TP
.PN /restoresymtab
Information passed between incremental restores
.TP
.PN /dev/tty
Required for user interface
.SH See Also
dump(8), mkfs(8), mount(8), rrestore(8c)
.NXE "file system" "restoring incremental dumps"
.NXE "restore command"