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RESTORE(8) System management commands RESTORE(8)
NAME
restore - restore files or file systems from backups made with dump
SYNOPSIS
restore -C [-cdHklMvVy] [-b blocksize] [-D filesystem] [-f file] [-F script] [-L limit] [-s fileno] [-T directory]
restore -i [-acdhHklmMNouvVy] [-A file] [-b blocksize] [-f file] [-F script] [-Q file] [-s fileno] [-T directory]
restore -P file [-acdhHklmMNuvVy] [-b blocksize] [-f file] [-F script] [-s fileno] [-T directory] [-X filelist] [ file
... ]
restore -R [-cdHklMNuvVy] [-b blocksize] [-f file] [-F script] [-s fileno] [-T directory]
restore -r [-cdHklMNuvVy] [-b blocksize] [-f file] [-F script] [-s fileno] [-T directory]
restore -t [-cdhHklMNuvVy] [-A file] [-b blocksize] [-f file] [-F script] [-Q file] [-s fileno] [-T directory] [-X
filelist] [ file ... ]
restore -x [-adchHklmMNouvVy] [-A file] [-b blocksize] [-f file] [-F script] [-Q file] [-s fileno] [-T directory] [-X
filelist] [ file ... ]
DESCRIPTION
The restore command performs the inverse function of dump(8). A full backup of a file system may be restored and subse-
quent incremental backups layered on top of it. Single files and directory subtrees may be restored from full or partial
backups. Restore works across a network; to do this see the -f flag described below. Other arguments to the command are
file or directory names specifying the files that are to be restored. Unless the -h flag is specified (see below), the
appearance of a directory name refers to the files and (recursively) subdirectories of that directory.
Exactly one of the following flags is required:
-C This mode allows comparison of files from a dump. Restore reads the backup and compares its contents with files
present on the disk. It first changes its working directory to the root of the filesystem that was dumped and com-
pares the tape with the files in its new current directory. See also the -L flag described below.
-i This mode allows interactive restoration of files from a dump. After reading in the directory information from the
dump, restore provides a shell like interface that allows the user to move around the directory tree selecting
files to be extracted. The available commands are given below; for those commands that require an argument, the
default is the current directory.
add [arg]
The current directory or specified argument is added to 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 -h flag is spec-
ified on the command line). Files that are on the extraction list are prepended with a "*" when they are
listed by ls.
cd arg Change the current working directory to the specified argument.
delete [arg]
The current directory or specified argument is deleted from the list of files to be extracted. If a direc-
tory is specified, then it and all its descendents are deleted from the extraction list (unless the -h flag
is specified on the command line). The most expedient 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.
extract
All files on the extraction list are extracted from the dump. Restore will ask which volume the user
wishes to mount. The fastest way to extract a f ew files is to start with the last volume and work towards
the first volume.
help List a summary of the available commands.
ls [arg]
List the current or specified directory. Entries that are directories are appended with a "/". Entries that
have been marked for extraction are prepended with a "*". If the verbose flag is set, the inode number of
each entry is also listed.
pwd Print the full pathname of the current working directory.
quit Restore immediately exits, even if the extraction list is not empty.
setmodes
All directories that have been added to the extraction list have their owner, modes, and times set; nothing
is extracted from the dump. This is useful for cleaning up after a restore has been prematurely aborted.
verbose
The sense of the -v flag is toggled. When set, the verbose flag causes the ls command to list the inode
numbers of all entries. It also causes restore to print out information about each file as it is extracted.
-P file
Restore creates a new Quick File Access file file from an existing dump file without restoring its contents.
-R Restore requests a particular tape of a multi-volume set on which to restart a full restore (see the -r flag
below). This is useful if the restore has been interrupted.
-r Restore (rebuild) a file system. The target file system should be made pristine with mke2fs(8), mounted, and the
user cd'd into the pristine file system before starting the restoration of the initial level 0 backup. If the
level 0 restores successfully, the -r flag may be used to restore any necessary incremental backups on top of the
level 0. The -r flag precludes an interactive file extraction and can be detrimental to one's health (not to men-
tion the disk) if not used carefully. An example:
mke2fs /dev/sda1
mount /dev/sda1 /mnt
cd /mnt
restore rf /dev/st0
Note that restore leaves a file restoresymtable in the root directory to pass information between incremental
restore passes. This file should be removed when the last incremental has been restored.
Restore, in conjunction with mke2fs(8) and dump(8), may be used to modify file system parameters such as size or
block size.
-t The names of the specified files are listed if they occur on the backup. If no file argument is given, the root
directory is listed, which results in the entire content of the backup being listed, unless the -h flag has been
specified. Note that the -t flag replaces the function of the old dumpdir(8) program. See also the -X option
below.
-x The named files are read from the given media. If a named file matches a directory whose contents are on the
backup and the -h flag is not specified, the directory is recursively extracted. The owner, modification time, and
mode are restored (if possible). If no file argument is given, the root directory is extracted, which results in
the entire content of the backup being extracted, unless the -h flag has been specified. See also the -X option
below.
OPTIONS
The following additional options may be specified:
-a In -i or -x mode, restore does ask the user for the volume number on which the files to be extracted are supposed
to be (in order to minimise the time by reading only the interesting volumes). The -a option disables this behav-
iour and reads all the volumes starting with 1. This option is useful when the operator does not know on which
volume the files to be extracted are and/or when he prefers the longer unattended mode rather than the shorter
interactive mode.
-A archive_file
Read the table of contents from archive_file instead of the media. This option can be used in combination with the
-t, -i, or -x options, making it possible to check whether files are on the media without having to mount the
media.
-b blocksize
The number of kilobytes per dump record. If the -b option is not specified, restore tries to determine the media
block size dynamically.
-c Normally, restore will try to determine dynamically whether the dump was made from an old (pre-4.4) or new format
file system. The -c flag disables this check, and only allows reading a dump in the old format.
-d The -d (debug) flag causes restore to print debug information.
-D filesystem
The -D flag allows the user to specify the filesystem name when using restore with the -C option to check the
backup.
-f file
Read the backup from file; file may be a special device file like /dev/st0 (a tape drive), /dev/sda1 (a disk
drive), an ordinary file, or - (the standard input). If the name of the file is of the form host:file or
user@host:file, restore reads from the named file on the remote host using rmt(8).
-F script
Run script at the beginning of each tape. The device name and the current volume number are passed on the command
line. The script must return 0 if restore should continue without asking the user to change the tape, 1 if restore
should continue but ask the user to change the tape. Any other exit code will cause restore to abort. For security
reasons, restore reverts back to the real user ID and the real group ID before running the script.
-h Extract the actual directory, rather than the files that it references. This prevents hierarchical restoration of
complete subtrees from the dump.
-H hash_size
Use a hashtable having the specified number of entries for storing the directories entries instead of a linked
list. This hashtable will considerably speed up inode lookups (visible especially in interactive mode when
adding/removing files from the restore list), but at the price of much more memory usage. The default value is 1,
meaning no hashtable is used.
-k Use Kerberos authentication when contacting the remote tape server. (Only available if this options was enabled
when restore was compiled.)
-l When doing remote restores, assume the remote file is a regular file (instead of a tape device). If you're restor-
ing a remote compressed file, you will need to specify this option or restore will fail to access it correctly.
-L limit
The -L flag allows the user to specify a maximal number of miscompares when using restore with the -C option to
check the backup. If this limit is reached, restore will abort with an error message. A value of 0 (the default
value) disables the check.
-m Extract by inode numbers rather than by file name. This is useful if only a few files are being extracted, and one
wants to avoid regenerating the complete pathname to the file.
-M Enables the multi-volume feature (for reading dumps made using the -M option of dump). The name specified with -f
is treated as a prefix and restore tries to read in sequence from <prefix>001, <prefix>002 etc.
-N The -N flag causes restore to perform a full execution as requested by one of -i, -R, -r, t or x command without
actually writing any file on disk.
-o The -o flag causes restore to automatically restore the current directory permissions without asking the operator
whether to do so in one of -i or -x modes.
-Q file
Use the file file in order to read tape position as stored using the dump Quick File Access mode, in one of -i, -x
or -t mode.
It is recommended to set up the st driver to return logical tape positions rather than physical before calling
dump/restore with parameter -Q. Since not all tape devices support physical tape positions those tape devices
return an error during dump/restore when the st driver is set to the default physical setting. Please see the
st(4) man page, option MTSETDRVBUFFER , or the mt(1) man page, on how to set the driver to return logical tape
positions.
Before calling restore with parameter -Q, always make sure the st driver is set to return the same type of tape
position used during the call to dump. Otherwise restore may be confused.
This option can be used when restoring from local or remote tapes (see above) or from local or remote files.
-s fileno
Read from the specified fileno on a multi-file tape. File numbering starts at 1.
-T directory
The -T flag allows the user to specify a directory to use for the storage of temporary files. The default value is
/tmp. This flag is most useful when restoring files after having booted from a floppy. There might be little or
no space on the floppy filesystem, but another source of space might exist.
-u When creating certain types of files, restore may generate a warning diagnostic if they already exist in the tar-
get directory. To prevent this, the -u (unlink) flag causes restore to remove old entries before attempting to
create new ones.
-v Normally restore does its work silently. The -v (verbose) flag causes it to type the name of each file it treats
preceded by its file type.
-V Enables reading multi-volume non-tape mediums like CDROMs.
-X filelist
Read list of files to be listed or extracted from the text file filelist in addition to those specified on the
command line. This can be used in conjunction with the -t or -x commands. The file filelist should contain file
names separated by newlines. filelist may be an ordinary file or - (the standard input).
-y Do not ask the user whether to abort the restore in the event of an error. Always try to skip over the bad
block(s) and continue.
(The 4.3BSD option syntax is implemented for backward compatibility but is not documented here.)
DIAGNOSTICS
Complains if it gets a read error. If y has been specified, or the user responds y, restore will attempt to continue the
restore.
If a backup was made using more than one tape volume, restore will notify the user when it is time to mount the next vol-
ume. If the -x or -i flag has been specified, restore will also ask which volume the user wishes to mount. The fastest
way to extract a few files is to start with the last volume, and work towards the first volume.
There are numerous consistency checks that can be listed by restore. Most checks are self-explanatory or can "never hap-
pen". Common errors are given below:
Converting to new file system format
A dump tape created from the old file system has been loaded. It is automatically converted to the new file system
format.
<filename>: not found on tape
The specified file name was listed in the tape directory, but was not found on the tape. This is caused by tape
read errors while looking for the file, and from using a dump tape created on an active file system.
expected next file <inumber>, got <inumber>
A file that was not listed in the directory showed up. This can occur when using a dump created on an active file
system.
Incremental dump too low
When doing an incremental restore, a dump that was written before the previous incremental dump, or that has too
low an incremental level has been loaded.
Incremental dump too high
When doing an incremental restore, a dump that does not begin its coverage where the previous incremental dump
left off, or that has too high an incremental level has been loaded.
Tape read error while restoring <filename>
Tape read error while skipping over inode <inumber>
Tape read error while trying to resynchronize
A tape (or other media) read error has occurred. If a file name is specified, its contents are probably partially
wrong. If an inode is being skipped or the tape is trying to resynchronize, no extracted files have been cor-
rupted, though files may not be found on the tape.
resync restore, skipped <num> blocks
After a dump read error, restore may have to resynchronize itself. This message lists the number of blocks that
were skipped over.
EXIT STATUS
Restore exits with zero status on success. Tape errors are indicated with an exit code of 1.
When doing a comparison of files from a dump, an exit code of 2 indicates that some files were modified or deleted since
the dump was made.
ENVIRONMENT
If the following environment variable exists it will be utilized by restore:
TAPE If no -f option was specified, restore will use the device specified via TAPE as the dump device. TAPE may be of
the form tapename, host:tapename or user@host:tapename.
TMPDIR The directory given in TMPDIR will be used instead of /tmp to store temporary files.
RMT The environment variable RMT will be used to determine the pathname of the remote rmt(8) program.
RSH Restore uses the contents of this variable to determine the name of the remote shell command to use when doing a
network restore (rsh, ssh etc.). If this variable is not set, rcmd(3) will be used, but only root will be able to
do a network restore.
FILES
/dev/st0
the default tape drive
/tmp/rstdir*
file containing directories on the tape
/tmp/rstmode*
owner, mode, and time stamps for directories
./restoresymtable
information passed between incremental restores
SEE ALSO
dump(8), mount(8), mke2fs(8), rmt(8)
BUGS
Restore can get confused when doing incremental restores from dumps that were made on active file systems.
A level 0 dump must be done after a full restore. Because restore runs in user code, it has no control over inode alloca-
tion; thus a full dump must be done to get a new set of directories reflecting the new inode numbering, even though the
content of the files is unchanged.
The temporary files /tmp/rstdir* and /tmp/rstmode* are generated with a unique name based on the date of the dump and the
process ID (see mktemp(3)), except when -r or -R is used. Because -R allows you to restart a -r operation that may have
been interrupted, the temporary files should be the same across different processes. In all other cases, the files are
unique because it is possible to have two different dumps started at the same time, and separate operations shouldn't
conflict with each other.
To do a network restore, you have to run restore as root or use a remote shell replacement (see RSH variable). This is
due to the previous security history of dump and restore. ( restore is written to be setuid root, but we are not certain
all bugs are gone from the code - run setuid at your own risk.)
At the end of restores in -i or -x modes (unless -o option is in use), restore will ask the operator whether to set the
permissions on the current directory. If the operator confirms this action, the permissions on the directory from where
restore was launched will be replaced by the permissions on the dumped root inode. Although this behaviour is not really
a bug, it has proven itself to be confusing for many users, so it is recommended to answer 'no', unless you're performing
a full restore and you do want to restore the permissions on '/'.
It should be underlined that because it runs in user code, restore , when run with the -C option, sees the files as the
kernel presents them, whereas dump sees all the files on a given filesystem. In particular, this can cause some confusion
when comparing a dumped filesystem a part of which is hidden by a filesystem mounted on top of it.
AUTHOR
The dump/restore backup suite was ported to Linux's Second Extended File System by Remy Card <cardATLinux.Org>. He
maintained the initial versions of dump (up and including 0.4b4, released in January 1997).
Starting with 0.4b5, the new maintainer is Stelian Pop <stelianATpopies.net>.
AVAILABILITY
The dump/restore backup suite is available from <http://dump.sourceforge.net>;
HISTORY
The restore command appeared in 4.2BSD.
BSD version 0.4b43 of June 11, 2010 RESTORE(8)
