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32 .\" $Id: restore.8.in,v 1.25 2002/02/04 11:18:46 stelian Exp $
33 .\"
34 .Dd __DATE__
35 .Dt RESTORE 8
36 .Os "restore __VERSION__"
37 .Sh NAME
38 .Nm restore
39 .Nd "restore files or file systems from backups made with dump"
40 .Sh SYNOPSIS
41 .Nm restore
42 .Fl C
43 .Op Fl cklMvVy
44 .Op Fl b Ar blocksize
45 .Op Fl D Ar filesystem
46 .Op Fl f Ar file
47 .Op Fl F Ar script
48 .Op Fl L Ar limit
49 .Op Fl s Ar fileno
50 .Op Fl T Ar directory
51 .Nm restore
52 .Fl i
53 .Op Fl achklmMNuvVy
54 .Op Fl A Ar file
55 .Op Fl b Ar blocksize
56 .Op Fl f Ar file
57 .Op Fl F Ar script
58 .Op Fl Q Ar file
59 .Op Fl s Ar fileno
60 .Op Fl T Ar directory
61 .Nm restore
62 .Fl P Ar file
63 .Op Fl achklmMNuvVy
64 .Op Fl A Ar file
65 .Op Fl b Ar blocksize
66 .Op Fl f Ar file
67 .Op Fl F Ar script
68 .Op Fl s Ar fileno
69 .Op Fl T Ar directory
70 .Op Fl X Ar filelist
71 .Op file ...
72 .Nm restore
73 .Fl R
74 .Op Fl cklMNuvVy
75 .Op Fl b Ar blocksize
76 .Op Fl f Ar file
77 .Op Fl F Ar script
78 .Op Fl s Ar fileno
79 .Op Fl T Ar directory
80 .Nm restore
81 .Fl r
82 .Op Fl cklMNuvVy
83 .Op Fl b Ar blocksize
84 .Op Fl f Ar file
85 .Op Fl F Ar script
86 .Op Fl s Ar fileno
87 .Op Fl T Ar directory
88 .Nm restore
89 .Fl t
90 .Op Fl chklMNuvVy
91 .Op Fl A Ar file
92 .Op Fl b Ar blocksize
93 .Op Fl f Ar file
94 .Op Fl F Ar script
95 .Op Fl Q Ar file
96 .Op Fl s Ar fileno
97 .Op Fl T Ar directory
98 .Op Fl X Ar filelist
99 .Op file ...
100 .Nm restore
101 .Fl x
102 .Op Fl achklmMNuvVy
103 .Op Fl A Ar file
104 .Op Fl b Ar blocksize
105 .Op Fl f Ar file
106 .Op Fl F Ar script
107 .Op Fl Q Ar file
108 .Op Fl s Ar fileno
109 .Op Fl T Ar directory
110 .Op Fl X Ar filelist
111 .Op file ...
112 .Pp
113 .in
114 (The
115 .Bx 4.3
116 option syntax is implemented for backward compatibility but
117 is not documented here.)
118 .Sh DESCRIPTION
119 The
120 .Nm restore
121 command performs the inverse function of
122 .Xr dump 8 .
123 A full backup of a file system may be restored and
124 subsequent incremental backups layered on top of it.
125 Single files and
126 directory subtrees may be restored from full or partial
127 backups.
128 .Nm Restore
129 works across a network;
130 to do this see the
131 .Fl f
132 flag described below.
133 Other arguments to the command are file or directory
134 names specifying the files that are to be restored.
135 Unless the
136 .Fl h
137 flag is specified (see below),
138 the appearance of a directory name refers to
139 the files and (recursively) subdirectories of that directory.
140 .Pp
141 Exactly one of the following flags is required:
142 .Bl -tag -width Ds
143 .It Fl C
144 This mode allows comparison of files from a dump.
145 .Nm Restore
146 reads the backup and compares its contents with files present on the
147 disk.
148 It first changes its working directory to the root of the filesystem
149 that was dumped and compares the tape with the files in its new
150 current directory.
151 See also the
152 .Fl L
153 flag described below.
154 .It Fl i
155 This mode allows interactive restoration of files from a dump.
156 After reading in the directory information from the dump,
157 .Nm restore
158 provides a shell like interface that allows the user to move
159 around the directory tree selecting files to be extracted.
160 The available commands are given below;
161 for those commands that require an argument,
162 the default is the current directory.
163 .Bl -tag -width Fl
164 .It Ic add Op Ar arg
165 The current directory or specified argument is added to the list of
166 files to be extracted.
167 If a directory is specified, then it and all its descendents are
168 added to the extraction list
169 (unless the
170 .Fl h
171 flag is specified on the command line).
172 Files that are on the extraction list are prepended with a
173 .Dq \&*
174 when they are listed by
175 .Ic ls .
176 .It Ic \&cd Ar arg
177 Change the current working directory to the specified argument.
178 .It Ic delete Op Ar arg
179 The current directory or specified argument is deleted from the list of
180 files to be extracted.
181 If a directory is specified, then it and all its descendents are
182 deleted from the extraction list
183 (unless the
184 .Fl h
185 flag is specified on the command line).
186 The most expedient way to extract most of the files from a directory
187 is to add the directory to the extraction list and then delete
188 those files that are not needed.
189 .It Ic extract
190 All files on the extraction list are extracted
191 from the dump.
192 .Nm Restore
193 will ask which volume the user wishes to mount.
194 The fastest way to extract a few files is to
195 start with the last volume and work towards the first volume.
196 .It Ic help
197 List a summary of the available commands.
198 .It Ic \&ls Op Ar arg
199 List the current or specified directory.
200 Entries that are directories are appended with a
201 .Dq \&* .
202 Entries that have been marked for extraction are prepended with a ``*''.
203 If the verbose
204 flag is set, the inode number of each entry is also listed.
205 .It Ic pwd
206 Print the full pathname of the current working directory.
207 .It Ic quit
208 Restore immediately exits,
209 even if the extraction list is not empty.
210 .It Ic setmodes
211 All directories that have been added to the extraction list
212 have their owner, modes, and times set;
213 nothing is extracted from the dump.
214 This is useful for cleaning up after a restore has been prematurely aborted.
215 .It Ic verbose
216 The sense of the
217 .Fl v
218 flag is toggled.
219 When set, the verbose flag causes the
220 .Ic ls
221 command to list the inode numbers of all entries.
222 It also causes
223 .Nm restore
224 to print out information about each file as it is extracted.
225 .El
226 .It Fl P Ar file
227 .Nm Restore
228 creates a new Quick File Access file
229 .Ar file
230 from an existing dump file without restoring its contents.
231 .It Fl R
232 .Nm Restore
233 requests a particular tape of a multi-volume set on which to restart
234 a full restore
235 (see the
236 .Fl r
237 flag below).
238 This is useful if the restore has been interrupted.
239 .It Fl r
240 Restore (rebuild) a file system.
241 The target file system should be made pristine with
242 .Xr mke2fs 8 ,
243 mounted, and the user
244 .Xr cd Ns 'd
245 into the pristine file system
246 before starting the restoration of the initial level 0 backup. If the
247 level 0 restores successfully, the
248 .Fl r
249 flag may be used to restore
250 any necessary incremental backups on top of the level 0.
251 The
252 .Fl r
253 flag precludes an interactive file extraction and can be
254 detrimental to one's health (not to mention the disk) if not used carefully.
255 An example:
256 .Bd -literal -offset indent
257 mke2fs /dev/sda1
258 mount /dev/sda1 /mnt
259 cd /mnt
260
261 restore rf /dev/st0
262 .Ed
263 .Pp
264 Note that
265 .Nm restore
266 leaves a file
267 .Pa restoresymtable
268 in the root directory to pass information between incremental
269 restore passes.
270 This file should be removed when the last incremental has been
271 restored.
272 .Pp
273 .Nm Restore ,
274 in conjunction with
275 .Xr mke2fs 8
276 and
277 .Xr dump 8 ,
278 may be used to modify file system parameters
279 such as size or block size.
280 .It Fl t
281 The names of the specified files are listed if they occur
282 on the backup.
283 If no file argument is given,
284 the root directory is listed,
285 which results in the entire content of the
286 backup being listed,
287 unless the
288 .Fl h
289 flag has been specified.
290 Note that the
291 .Fl t
292 flag replaces the function of the old
293 .Xr dumpdir 8
294 program.
295 See also the
296 .Fl X
297 option below.
298 .ne 1i
299 .It Fl x
300 The named files are read from the given media.
301 If a named file matches a directory whose contents
302 are on the backup
303 and the
304 .Fl h
305 flag is not specified,
306 the directory is recursively extracted.
307 The owner, modification time,
308 and mode are restored (if possible).
309 If no file argument is given,
310 the root directory is extracted,
311 which results in the entire content of the
312 backup being extracted,
313 unless the
314 .Fl h
315 flag has been specified.
316 See also the
317 .Fl X
318 option below.
319 .El
320 .Pp
321 The following additional options may be specified:
322 .Bl -tag -width Ds
323 .It Fl a
324 In
325 .Fl i
326 or
327 .Fl x
328 mode,
329 .Nm restore
330 does ask the user for the volume number on which the files to
331 be extracted are supposed to be (in order to minimise the time
332 be reading only the interesting volumes). The
333 .Fl a
334 option disables this behaviour and reads all the volumes starting
335 with 1. This option is useful when the operator does not know on which
336 volume the files to be extracted are and/or when he prefers the
337 longer unattended mode rather than the shorter interactive mode.
338 .It Fl A Ar archive_file
339 Read the table of contents from
340 .Ar archive_file
341 instead of the media. This option can be used in combination with the
342 .Fl t,
343 .Fl i,
344 or
345 .Fl x
346 options, making it possible to check whether files are on the media
347 without having to mount the media.
348 .It Fl b Ar blocksize
349 The number of kilobytes per dump record.
350 If the
351 .Fl b
352 option is not specified,
353 .Nm restore
354 tries to determine the media block size dynamically.
355 .It Fl c
356 Normally,
357 .Nm restore
358 will try to determine dynamically whether the dump was made from an
359 old (pre-4.4) or new format file system. The
360 .Fl c
361 flag disables this check, and only allows reading a dump in the old
362 format.
363 .It Fl D Ar filesystem
364 The
365 .Fl D
366 flag allows the user to specify the filesystem name when using
367 .Nm restore
368 with the
369 .Fl C
370 option to check the backup.
371 .It Fl f Ar file
372 Read the backup from
373 .Ar file ;
374 .Ar file
375 may be a special device file
376 like
377 .Pa /dev/st0
378 (a tape drive),
379 .Pa /dev/sda1
380 (a disk drive),
381 an ordinary file,
382 or
383 .Ql Fl
384 (the standard input).
385 If the name of the file is of the form
386 .Dq host:file
387 or
388 .Dq user@host:file ,
389 .Nm restore
390 reads from the named file on the remote host using
391 .Xr rmt 8 .
392 .Pp
393 .It Fl F Ar script
394 Run script at the beginning of each tape. The device name and the
395 current volume number are passed on the command line.
396 The script must return 0 if
397 .Nm
398 should continue without asking the user to change the tape, 1 if
399 .Nm
400 should continue but ask the user to change the tape.
401 Any other exit code will cause
402 .Nm
403 to abort.
404 For security reasons,
405 .Nm
406 reverts back to the real user ID and the real group ID before
407 running the script.
408 .It Fl h
409 Extract the actual directory,
410 rather than the files that it references.
411 This prevents hierarchical restoration of complete subtrees
412 from the dump.
413 .It Fl k
414 Use Kerberos authentication when contacting the remote tape server.
415 (Only available if this options was enabled when
416 .Nm restore
417 was compiled.)
418 .It Fl l
419 When doing remote restores, assume the remote file is a
420 regular file (instead of a tape device). If you're restoring
421 a remote compressed file, you will need to specify this
422 option or
423 .Nm restore
424 will fail to access it correctly.
425 .It Fl L Ar limit
426 The
427 .Fl L
428 flag allows the user to specify a maximal number of miscompares
429 when using
430 .Nm restore
431 with the
432 .Fl C
433 option to check the backup. If this limit is reached,
434 .Nm restore
435 will abort with an error message. A value of 0 (the default value)
436 disables the check.
437 .It Fl m
438 Extract by inode numbers rather than by file name.
439 This is useful if only a few files are being extracted,
440 and one wants to avoid regenerating the complete pathname
441 to the file.
442 .It Fl M
443 Enables the multi-volume feature (for reading dumps made using
444 the
445 .Fl M
446 option of dump). The name specified with
447 .Fl f
448 is treated as a prefix and
449 .Nm
450 tries to read in sequence from <prefix>001, <prefix>002 etc.
451 .It Fl N
452 The
453 .Fl N
454 flag causes
455 .Nm
456 to perform a full execution as requested by one of
457 .Fl i,
458 .Fl R,
459 .Fl r,
460 .Fl t
461 or
462 .Fl x
463 command without actually writing any file on disk.
464 .It Fl Q Ar file
465 Use the file
466 .Ar file
467 in order to read tape position as stored using the dump Quick File
468 Access mode, in one of
469 .Fl i,
470 .Fl x
471 or
472 .Fl t
473 mode.
474 .Pp
475 It is recommended to set up the st driver to return logical tape
476 positions rather than physical before calling dump/restore with
477 parameter Q. Since not all tape devices support physical tape
478 positions those tape devices return an error during dump/restore when
479 the st driver is set to the default physical setting.
480 Please see the st man page, option MTSETDRVBUFFER, or the mt man
481 page, on how to set the driver to return logical tape positions.
482 .Pp
483 Before calling restore with parameter Q, always make sure the st
484 driver is set to return the same type of tape position used during the
485 call to dump. Otherwise restore may be confused.
486 .Pp
487 This option can be used when restoring from local or remote tapes
488 (see above) or from local or remote files.
489 .It Fl s Ar fileno
490 Read from the specified
491 .Ar fileno
492 on a multi-file tape.
493 File numbering starts at 1.
494 .It Fl T Ar directory
495 The
496 .Fl T
497 flag allows the user to specify a directory to use for the storage of
498 temporary files. The default value is /tmp. This flag is most useful
499 when restoring files after having booted from a floppy. There might be little
500 or no space on the floppy filesystem, but another source of space might exist.
501 .It Fl u
502 When creating certain types of files, restore may generate a warning
503 diagnostic if they already exist in the target directory.
504 To prevent this, the
505 .Fl u
506 (unlink) flag causes restore to remove old entries before attempting
507 to create new ones.
508 .It Fl v
509 Normally
510 .Nm restore
511 does its work silently.
512 The
513 .Fl v
514 (verbose)
515 flag causes it to type the name of each file it treats
516 preceded by its file type.
517 .It Fl V
518 Enables reading multi-volume non-tape mediums like CDROMs.
519 .It Fl X Ar filelist
520 Read list of files to be listed or extracted from the text file
521 .Ar filelist
522 in addition to those specified on the command line. This can be used in
523 conjunction with the
524 .Fl t
525 or
526 .Fl x
527 commands. The file
528 .Ar filelist
529 should contain file names separated by newlines.
530 .Ar filelist
531 may be an ordinary file or
532 .Ql Fl
533 (the standard input).
534 .It Fl y
535 Do not ask the user whether to abort the restore in the event of an error.
536 Always try to skip over the bad block(s) and continue.
537 .El
538 .Sh DIAGNOSTICS
539 Complains if it gets a read error.
540 If
541 .Fl y
542 has been specified, or the user responds
543 .Ql y ,
544 .Nm restore
545 will attempt to continue the restore.
546 .Pp
547 If a backup was made using more than one tape volume,
548 .Nm restore
549 will notify the user when it is time to mount the next volume.
550 If the
551 .Fl x
552 or
553 .Fl i
554 flag has been specified,
555 .Nm restore
556 will also ask which volume the user wishes to mount.
557 The fastest way to extract a few files is to
558 start with the last volume, and work towards the first volume.
559 .Pp
560 There are numerous consistency checks that can be listed by
561 .Nm restore .
562 Most checks are self-explanatory or can
563 .Dq never happen .
564 Common errors are given below.
565 .Pp
566 .Bl -tag -width Ds -compact
567 .It Converting to new file system format
568 A dump tape created from the old file system has been loaded.
569 It is automatically converted to the new file system format.
570 .Pp
571 .It <filename>: not found on tape
572 The specified file name was listed in the tape directory,
573 but was not found on the tape.
574 This is caused by tape read errors while looking for the file,
575 and from using a dump tape created on an active file system.
576 .Pp
577 .It expected next file <inumber>, got <inumber>
578 A file that was not listed in the directory showed up.
579 This can occur when using a dump created on an active file system.
580 .Pp
581 .It Incremental dump too low
582 When doing an incremental restore,
583 a dump that was written before the previous incremental dump,
584 or that has too low an incremental level has been loaded.
585 .Pp
586 .It Incremental dump too high
587 When doing an incremental restore,
588 a dump that does not begin its coverage where the previous incremental
589 dump left off,
590 or that has too high an incremental level has been loaded.
591 .Pp
592 .It Tape read error while restoring <filename>
593 .It Tape read error while skipping over inode <inumber>
594 .It Tape read error while trying to resynchronize
595 A tape (or other media) read error has occurred.
596 If a file name is specified,
597 its contents are probably partially wrong.
598 If an inode is being skipped or the tape is trying to resynchronize,
599 no extracted files have been corrupted,
600 though files may not be found on the tape.
601 .Pp
602 .It resync restore, skipped <num> blocks
603 After a dump read error,
604 .Nm restore
605 may have to resynchronize itself.
606 This message lists the number of blocks that were skipped over.
607 .El
608 .Pp
609 .Nm Restore
610 exits with zero status on success.
611 Tape errors are indicated with an exit code of 1.
612 .Pp
613 When doing a comparison of files from a dump, an exit code
614 of 2 indicates that some files were modified or deleted since
615 the dump was made.
616 .Sh ENVIRONMENT
617 If the following environment variable exists it will be utilized by
618 .Nm restore :
619 .Pp
620 .Bl -tag -width "TMPDIR" -compact
621 .It Ev TAPE
622 If no -f option was specified,
623 .Nm
624 will use the device specified via
625 .Ev TAPE
626 as the dump device.
627 .Ev TAPE
628 may be of the form
629 .Qq tapename ,
630 .Qq host:tapename
631 or
632 .Qq user@host:tapename .
633 .It Ev TMPDIR
634 The directory given in
635 .Ev TMPDIR
636 will be used
637 instead of
638 .Pa /tmp
639 to store temporary files.
640 .It Ev RMT
641 The environment variable
642 .Ev RMT
643 will be used to determine the pathname of the remote
644 .Xr rmt 8
645 program.
646 .It Ev RSH
647 .Nm Restore
648 uses the contents of this variable to determine the name of the
649 remote shell command to use when doing a network restore (rsh, ssh etc.).
650 If this variable is not set,
651 .Xr rcmd 3
652 will be used, but only root will be able to do a network restore.
653 .El
654 .Sh FILES
655 .Bl -tag -width "./restoresymtable" -compact
656 .It Pa /dev/st0
657 the default tape drive
658 .It Pa /tmp/rstdir*
659 file containing directories on the tape
660 .It Pa /tmp/rstmode*
661 owner, mode, and time stamps for directories
662 .It Pa \&./restoresymtable
663 information passed between incremental restores
664 .El
665 .Sh SEE ALSO
666 .Xr dump 8 ,
667 .Xr mount 8 ,
668 .Xr mke2fs 8 ,
669 .Xr rmt 8
670 .Sh BUGS
671 .Nm Restore
672 can get confused when doing incremental restores from
673 dumps that were made on active file systems.
674 .Pp
675 A level 0 dump must be done after a full restore.
676 Because
677 .Nm restore
678 runs in user code,
679 it has no control over inode allocation;
680 thus a full dump must be done to get a new set of directories
681 reflecting the new inode numbering,
682 even though the content of the files is unchanged.
683 .Pp
684 The temporary files
685 .Pa /tmp/rstdir*
686 and
687 .Pa /tmp/rstmode*
688 are generated with a unique name based on the date of the dump
689 and the process ID (see
690 .Xr mktemp 3 ),
691 except when
692 .Fl r
693 or
694 .Fl R
695 is used.
696 Because
697 .Fl R
698 allows you to restart a
699 .Fl r
700 operation that may have been interrupted, the temporary files should
701 be the same across different processes.
702 In all other cases, the files are unique because it is possible to
703 have two different dumps started at the same time, and separate
704 operations shouldn't conflict with each other.
705 .Pp
706 To do a network restore, you have to run restore as root or use
707 a remote shell replacement (see RSH variable). This is due
708 to the previous security history of dump and restore. (restore is
709 written to be setuid root, but we are not certain all bugs are gone
710 from the restore code - run setuid at your own risk.)
711 .Sh AUTHOR
712 The
713 .Nm dump/restore
714 backup suite was ported to Linux's Second Extended File System
715 by Remy Card <card@Linux.EU.Org>. He maintained the initial versions
716 of dump (up and including 0.4b4, released in january 1997).
717 .Pp
718 Starting with 0.4b5, the new maintainer is Stelian Pop
719 .br
720 <stelian@popies.net>.
721 .Sh AVAILABILITY
722 The
723 .Nm dump/restore
724 backup suite is available from
725 .br
726 http://dump.sourceforge.net
727 .Sh HISTORY
728 The
729 .Nm restore
730 command appeared in
731 .Bx 4.2 .