restore/restore.8.in

   1 .\" Copyright (c) 1985, 1991, 1993
   2 .\"     The Regents of the University of California.  All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that the following conditions
   6 .\" are met:
   7 .\" 1. Redistributions of source code must retain the above copyright
   8 .\"    notice, this list of conditions and the following disclaimer.
   9 .\" 2. Redistributions in binary form must reproduce the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer in the
  11 .\"    documentation and/or other materials provided with the distribution.
  12 .\" 3. Neither the name of the University nor the names of its contributors
  13 .\"    may be used to endorse or promote products derived from this software
  14 .\"    without specific prior written permission.
  15 .\"
  16 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26 .\" SUCH DAMAGE.
  27 .\"
  28 .\"     $Id: restore.8.in,v 1.35 2009/06/18 09:42:12 stelian Exp $
  29 .\"
  30 .TH RESTORE 8 "version __VERSION__ of __DATE__" BSD "System management commands"
  31 .SH NAME
  32 restore \- restore files or file systems from backups made with dump
  33 .SH SYNOPSIS
  34 .B restore \-C
  35 [\fB\-cdHklMvVy\fR]
  36 [\fB\-b \fIblocksize\fR]
  37 [\fB\-D \fIfilesystem\fR]
  38 [\fB\-f \fIfile\fR]
  39 [\fB\-F \fIscript\fR]
  40 [\fB\-L \fIlimit\fR]
  41 [\fB\-s \fIfileno\fR]
  42 [\fB\-T \fIdirectory\fR]
  43 .PP
  44 .B restore \-i
  45 [\fB\-acdhHklmMNouvVy\fR]
  46 [\fB\-A \fIfile\fR]
  47 [\fB\-b \fIblocksize\fR]
  48 [\fB\-f \fIfile\fR]
  49 [\fB\-F \fIscript\fR]
  50 [\fB\-Q \fIfile\fR]
  51 [\fB\-s \fIfileno\fR]
  52 [\fB\-T \fIdirectory\fR]
  53 .PP
  54 .B restore \-P
  55 .I file
  56 [\fB\-acdhHklmMNuvVy\fR]
  57 [\fB\-b \fIblocksize\fR]
  58 [\fB\-f \fIfile\fR]
  59 [\fB\-F \fIscript\fR]
  60 [\fB\-s \fIfileno\fR]
  61 [\fB\-T \fIdirectory\fR]
  62 [\fB\-X \fIfilelist\fR]
  63 [ \fIfile ... \fR]
  64 .PP
  65 .B restore \-R
  66 [\fB\-cdHklMNuvVy\fR]
  67 [\fB\-b \fIblocksize\fR]
  68 [\fB\-f \fIfile\fR]
  69 [\fB\-F \fIscript\fR]
  70 [\fB\-s \fIfileno\fR]
  71 [\fB\-T \fIdirectory\fR]
  72 .PP
  73 .B restore \-r
  74 [\fB\-cdHklMNuvVy\fR]
  75 [\fB\-b \fIblocksize\fR]
  76 [\fB\-f \fIfile\fR]
  77 [\fB\-F \fIscript\fR]
  78 [\fB\-s \fIfileno\fR]
  79 [\fB\-T \fIdirectory\fR]
  80 .PP
  81 .B restore \-t
  82 [\fB\-cdhHklMNuvVy\fR]
  83 [\fB\-A \fIfile\fR]
  84 [\fB\-b \fIblocksize\fR]
  85 [\fB\-f \fIfile\fR]
  86 [\fB\-F \fIscript\fR]
  87 [\fB\-Q \fIfile\fR]
  88 [\fB\-s \fIfileno\fR]
  89 [\fB\-T \fIdirectory\fR]
  90 [\fB\-X \fIfilelist\fR]
  91 [ \fIfile ... \fR]
  92 .PP
  93 .B restore \-x
  94 [\fB\-adchHklmMNouvVy\fR]
  95 [\fB\-A \fIfile\fR]
  96 [\fB\-b \fIblocksize\fR]
  97 [\fB\-f \fIfile\fR]
  98 [\fB\-F \fIscript\fR]
  99 [\fB\-Q \fIfile\fR]
 100 [\fB\-s \fIfileno\fR]
 101 [\fB\-T \fIdirectory\fR]
 102 [\fB\-X \fIfilelist\fR]
 103 [ \fIfile ... \fR]
 104 .SH DESCRIPTION
 105 The
 106 .B restore
 107 command performs the inverse function of
 108 .BR dump (8).
 109 A full backup of a file system may be restored and subsequent incremental
 110 backups layered on top of it. Single files and directory subtrees may be
 111 restored from full or partial backups.
 112 .B Restore
 113 works across a network; to do this see the
 114 .B \-f
 115 flag described below. Other arguments to the command are file or directory
 116 names specifying the files that are to be restored. Unless the
 117 .B \-h
 118 flag is specified (see below), the appearance of a directory name refers to
 119 the files and (recursively) subdirectories of that directory.
 120 .PP
 121 Exactly one of the following flags is required:
 122 .TP
 123 .B \-C
 124 This mode allows comparison of files from a dump.
 125 .B Restore
 126 reads the backup and compares its contents with files present on the disk. It
 127 first changes its working directory to the root of the filesystem that was
 128 dumped and compares the tape with the files in its new current directory. See
 129 also the
 130 .B \-L
 131 flag described below.
 132 .TP
 133 .B \-i
 134 This mode allows interactive restoration of files from a dump. After reading in
 135 the directory information from the dump,
 136 .B restore
 137 provides a shell like interface that allows the user to move around the
 138 directory tree selecting files to be extracted. The available commands are
 139 given below; for those commands that require an argument, the default is the
 140 current directory.
 141 .RS
 142 .TP
 143 .B add \fR[\fIarg\fR]
 144 The current directory or specified argument is added to the list of files to be
 145 extracted.  If a directory is specified, then it and all its descendents are
 146 added to the extraction list (unless the
 147 .B \-h
 148 flag is specified on the command line). Files that are on the extraction list
 149 are prepended with a \*(lq*\*(rq when they are listed by
 150 .BR ls .
 151 .TP
 152 .BI cd " arg"
 153 Change the current working directory to the specified argument.
 154 .TP
 155 .B delete \fR[\fIarg\fR]
 156 The current directory or specified argument is deleted from the list of files
 157 to be extracted. If a directory is specified, then it and all its descendents
 158 are deleted from the extraction list (unless the
 159 .B \-h
 160 flag is specified on the command line). The most expedient way to extract most
 161 of the files from a directory is to add the directory to the extraction list
 162 and then delete those files that are not needed.
 163 .TP
 164 .B extract
 165 All files on the extraction list are extracted from the dump.
 166 .B Restore
 167 will ask which volume the user wishes to mount. The fastest way to extract a f
 168 ew files is to start with the last volume and work towards the first volume.
 169 .TP
 170 .B help
 171 List a summary of the available commands.
 172 .TP
 173 .B ls \fR[\fIarg\fR]
 174 List the current or specified directory. Entries that are directories are
 175 appended with a \*(lq/\*(rq. Entries that have been marked for extraction are
 176 prepended with a \*(lq*\*(rq. If the verbose flag is set, the inode number of
 177 each entry is also listed.
 178 .TP
 179 .B pwd
 180 Print the full pathname of the current working directory.
 181 .TP
 182 .B quit
 183 .B Restore
 184 immediately exits, even if the extraction list is not empty.
 185 .TP
 186 .B setmodes
 187 All directories that have been added to the extraction list have their owner,
 188 modes, and times set; nothing is extracted from the dump. This is useful for
 189 cleaning up after a
 190 .B restore
 191 has been prematurely aborted.
 192 .TP
 193 .B verbose
 194 The sense of the
 195 .B \-v
 196 flag is toggled. When set, the verbose flag causes the
 197 .B ls
 198 command to list the inode numbers of all entries. It also causes
 199 .B restore
 200 to print out information about each file as it is extracted.
 201 .RE
 202 .TP
 203 .BI \-P " file"
 204 .B Restore
 205 creates a new Quick File Access file
 206 .I file
 207 from an existing dump file without restoring its contents.
 208 .TP
 209 .B \-R
 210 .B Restore
 211 requests a particular tape of a multi-volume set on which to restart a full
 212 restore (see the
 213 .B \-r
 214 flag below). This is useful if the restore has been interrupted.
 215 .TP
 216 .B \-r
 217 Restore (rebuild) a file system. The target file system should be made pristine
 218 with
 219 .BR mke2fs (8),
 220 mounted, and the user
 221 .BR cd 'd
 222 into the pristine file system before starting the restoration of the initial
 223 level 0 backup. If the level 0 restores successfully, the
 224 .B \-r
 225 flag may be used to restore any necessary incremental backups on top of the
 226 level 0. The
 227 .B \-r
 228 flag precludes an interactive file extraction and can be detrimental to one's
 229 health (not to mention the disk) if not used carefully. An example:
 230 .IP
 231 .RS 14
 232 .B mke2fs /dev/sda1
 233 .TP
 234 .B mount /dev/sda1 /mnt
 235 .TP
 236 .B cd /mnt
 237 .TP
 238 .B restore rf /dev/st0
 239 .RE
 240 .IP
 241 Note that
 242 .B restore
 243 leaves a file
 244 .I restoresymtable
 245 in the root directory to pass information between incremental restore passes.
 246 This file should be removed when the last incremental has been restored.
 247 .IP
 248 .BR Restore ,
 249 in conjunction with
 250 .BR mke2fs (8)
 251 and
 252 .BR dump (8),
 253 may be used to modify file system parameters such as size or block size.
 254 .TP
 255 .B \-t
 256 The names of the specified files are listed if they occur on the backup. If no
 257 file argument is given, the root directory is listed, which results in the
 258 entire content of the backup being listed, unless the
 259 .B \-h
 260 flag has been specified.  Note that the
 261 .B \-t
 262 flag replaces the function of the old
 263 .BR dumpdir (8)
 264 program.  See also the
 265 .B \-X
 266 option below.
 267 .TP
 268 .B \-x
 269 The named files are read from the given media. If a named file matches a
 270 directory whose contents are on the backup and the
 271 .B \-h
 272 flag is not specified, the directory is recursively extracted. The owner,
 273 modification time, and mode are restored (if possible). If no file argument is
 274 given, the root directory is extracted, which results in the entire content of
 275 the backup being extracted, unless the
 276 .B \-h
 277 flag has been specified.  See also the
 278 .B \-X
 279 option below.
 280 .SH OPTIONS
 281 The following additional options may be specified:
 282 .TP
 283 .B \-a
 284 In
 285 .B \-i
 286 or
 287 .B \-x
 288 mode,
 289 .B restore
 290 does ask the user for the volume number on which the files to be extracted are
 291 supposed to be (in order to minimise the time by reading only the interesting
 292 volumes). The
 293 .B \-a
 294 option disables this behaviour and reads all the volumes starting with 1. This
 295 option is useful when the operator does not know on which volume the files to
 296 be extracted are and/or when he prefers the longer unattended mode rather than
 297 the shorter interactive mode.
 298 .TP
 299 .BI \-A " archive_file"
 300 Read the table of contents from
 301 .I archive_file
 302 instead of the media. This option can be used in combination with the
 303 .BR \-t ,
 304 .BR \-i ,
 305 or
 306 .B \-x
 307 options, making it possible to check whether files are on the media without
 308 having to mount the media.
 309 .TP
 310 .BI \-b " blocksize"
 311 The number of kilobytes per dump record. If the
 312 .B \-b
 313 option is not specified,
 314 .B restore
 315 tries to determine the media block size dynamically.
 316 .TP
 317 .B \-c
 318 Normally,
 319 .B restore
 320 will try to determine dynamically whether the dump was made from an old
 321 (pre-4.4) or new format file system. The
 322 .B \-c
 323 flag disables this check, and only allows reading a dump in the old format.
 324 .TP
 325 .B \-d
 326 The
 327 .B \-d
 328 (debug) flag causes
 329 .B restore
 330 to print debug information.
 331 .TP
 332 .BI \-D " filesystem"
 333 The
 334 .B \-D
 335 flag allows the user to specify the filesystem name when using
 336 .B restore
 337 with the
 338 .B \-C
 339 option to check the backup.
 340 .TP
 341 .BI \-f " file"
 342 Read the backup from
 343 .IR file ;
 344 .I file
 345 may be a special device file like
 346 .I /dev/st0
 347 (a tape drive),
 348 .I /dev/sda1
 349 (a disk drive), an ordinary file, or
 350 .I \-
 351 (the standard input). If the name of the file is of the form
 352 .I host:file
 353 or
 354 .IR user@host:file ,
 355 .B restore
 356 reads from the named file on the remote host using
 357 .BR rmt (8).
 358 .TP
 359 .BI \-F " script"
 360 Run script at the beginning of each tape. The device name and the current
 361 volume number are passed on the command line. The script must return 0 if
 362 .B restore
 363 should continue without asking the user to change the tape, 1 if
 364 .B restore
 365 should continue but ask the user to change the tape. Any other exit code will
 366 cause
 367 .B restore
 368 to abort. For security reasons,
 369 .B restore
 370 reverts back to the real user ID and the real group ID before running the
 371 script.
 372 .TP
 373 .B \-h
 374 Extract the actual directory, rather than the files that it references. This
 375 prevents hierarchical restoration of complete subtrees from the dump.
 376 .TP
 377 .BI \-H " hash_size"
 378 Use a hashtable having the specified number of entries for storing the
 379 directories entries instead of a linked list. This hashtable will
 380 considerably speed up inode lookups (visible especially in interactive
 381 mode when adding/removing files from the restore list), but at the
 382 price of much more memory usage. The default value is 1, meaning no
 383 hashtable is used.
 384 .TP
 385 .B \-k
 386 Use Kerberos authentication when contacting the remote tape server. (Only
 387 available if this options was enabled when
 388 .B restore
 389 was compiled.)
 390 .TP
 391 .B \-l
 392 When doing remote restores, assume the remote file is a regular file (instead
 393 of a tape device). If you're restoring a remote compressed file, you will need
 394 to specify this option or
 395 .B restore
 396 will fail to access it correctly.
 397 .TP
 398 .BI \-L " limit"
 399 The
 400 .B \-L
 401 flag allows the user to specify a maximal number of miscompares when using
 402 .B restore
 403 with the
 404 .B \-C
 405 option to check the backup. If this limit is reached,
 406 .B restore
 407 will abort with an error message. A value of 0 (the default value) disables
 408 the check.
 409 .TP
 410 .B \-m
 411 Extract by inode numbers rather than by file name. This is useful if only a few
 412 files are being extracted, and one wants to avoid regenerating the complete
 413 pathname to the file.
 414 .TP
 415 .B \-M
 416 Enables the multi-volume feature (for reading dumps made using the
 417 .B \-M
 418 option of dump). The name specified with
 419 .B \-f
 420 is treated as a prefix and
 421 .B restore
 422 tries to read in sequence from
 423 .I <prefix>001, <prefix>002
 424 etc.
 425 .TP
 426 .B \-N
 427 The
 428 .B \-N
 429 flag causes
 430 .B restore
 431 to perform a full execution as requested by one of
 432 .BR \-i ,
 433 .BR \-R ,
 434 .BR \-r ,
 435 .B t
 436 or
 437 .B x
 438 command without actually writing any file on disk.
 439 .TP
 440 .B \-o
 441 The
 442 .B \-o
 443 flag causes
 444 .B restore
 445 to automatically restore the current directory permissions without asking the
 446 operator whether to do so in one of
 447 .B \-i
 448 or
 449 .B \-x
 450 modes.
 451 .TP
 452 .BI \-Q " file"
 453 Use the file
 454 .I file
 455 in order to read tape position as stored using the dump Quick File Access mode,
 456 in one of
 457 .BR \-i ,
 458 .B \-x
 459 or
 460 .B \-t
 461 mode.
 462 .IP
 463 It is recommended to set up the st driver to return logical tape positions
 464 rather than physical before calling
 465 .B dump/restore
 466 with parameter
 467 .BR \-Q .
 468 Since not all tape devices support physical tape positions those tape devices
 469 return an error during
 470 .B dump/restore
 471 when the st driver is set to the default physical setting. Please see the
 472 .BR st (4)
 473 man page, option
 474 .B MTSETDRVBUFFER
 475 , or the
 476 .BR mt(1)
 477 man page, on how to set the driver to return logical tape positions.
 478 .IP
 479 Before calling
 480 .B restore
 481 with parameter
 482 .BR \-Q ,
 483 always make sure the st driver is set to return the same type of tape position
 484 used during the call to
 485 .BR dump .
 486 Otherwise
 487 .B restore
 488 may be confused.
 489 .IP
 490 This option can be used when restoring from local or remote tapes (see above)
 491 or from local or remote files.
 492 .TP
 493 .BI \-s " fileno"
 494 Read from the specified
 495 .I fileno
 496 on a multi-file tape. File numbering starts at 1.
 497 .TP
 498 .BI \-T " directory"
 499 The
 500 .B \-T
 501 flag allows the user to specify a directory to use for the storage of temporary
 502 files. The default value is
 503 .IR /tmp .
 504 This flag is most useful when restoring files after having booted from a
 505 floppy. There might be little or no space on the floppy filesystem, but another
 506 source of space might exist.
 507 .TP
 508 .B \-u
 509 When creating certain types of files,
 510 .B restore
 511 may generate a warning diagnostic if they already exist in the target
 512 directory. To prevent this, the
 513 .B \-u
 514 (unlink) flag causes
 515 .B restore
 516 to remove old entries before attempting to create new ones.
 517 .TP
 518 .B \-v
 519 Normally
 520 .B restore
 521 does its work silently. The
 522 .B \-v
 523 (verbose) flag causes it to type the name of each file it treats preceded by
 524 its file type.
 525 .TP
 526 .B \-V
 527 Enables reading multi-volume non-tape mediums like CDROMs.
 528 .TP
 529 .BI \-X " filelist"
 530 Read list of files to be listed or extracted from the text file
 531 .I filelist
 532 in addition to those specified on the command line. This can be used in
 533 conjunction with the
 534 .B \-t
 535 or
 536 .B \-x
 537 commands. The file
 538 .I filelist
 539 should contain file names separated by newlines.
 540 .I filelist
 541 may be an ordinary file or
 542 .I -
 543 (the standard input).
 544 .TP
 545 .B \-y
 546 Do not ask the user whether to abort the restore in the event of an error.
 547 Always try to skip over the bad block(s) and continue.
 548 .PP
 549 (The 4.3BSD option syntax is implemented for backward compatibility but is not
 550 documented here.)
 551 .SH DIAGNOSTICS
 552 Complains if it gets a read error. If
 553 .B y
 554 has been specified, or the user responds
 555 .BR y ,
 556 .B restore
 557 will attempt to continue the restore.
 558 .PP
 559 If a backup was made using more than one tape volume,
 560 .B restore
 561 will notify the user when it is time to mount the next volume. If the
 562 .B \-x
 563 or
 564 .B \-i
 565 flag has been specified,
 566 .B restore
 567 will also ask which volume the user wishes to mount. The fastest way to extract
 568 a few files is to start with the last volume, and work towards the first volume.
 569 .PP
 570 There are numerous consistency checks that can be listed by
 571 .BR restore .
 572 Most checks are self-explanatory or can \*(lqnever happen\*(rq. Common errors
 573 are given below:
 574 .TP
 575 .I Converting to new file system format
 576 A dump tape created from the old file system has been loaded. It is
 577 automatically converted to the new file system format.
 578 .TP
 579 .I <filename>: not found on tape
 580 The specified file name was listed in the tape directory, but was not found on
 581 the tape. This is caused by tape read errors while looking for the file, and
 582 from using a dump tape created on an active file system.
 583 .TP
 584 .I expected next file <inumber>, got <inumber>
 585 A file that was not listed in the directory showed up. This can occur when
 586 using a dump created on an active file system.
 587 .TP
 588 .I Incremental dump too low
 589 When doing an incremental restore, a dump that was written before the previous
 590 incremental dump, or that has too low an incremental level has been loaded.
 591 .TP
 592 .I Incremental dump too high
 593 When doing an incremental restore, a dump that does not begin its coverage
 594 where the previous incremental dump left off, or that has too high an
 595 incremental level has been loaded.
 596 .TP
 597 .I Tape read error while restoring <filename>
 598 .TP
 599 .I Tape read error while skipping over inode <inumber>
 600 .TP
 601 .I Tape read error while trying to resynchronize
 602 A tape (or other media) read error has occurred. If a file name is specified,
 603 its contents are probably partially wrong. If an inode is being skipped or the
 604 tape is trying to resynchronize, no extracted files have been corrupted, though
 605 files may not be found on the tape.
 606 .TP
 607 .I resync restore, skipped <num> blocks
 608 After a dump read error,
 609 .B restore
 610 may have to resynchronize itself. This message lists the number of blocks that
 611 were skipped over.
 612 .SH EXIT STATUS
 613 .B Restore
 614 exits with zero status on success. Tape errors are indicated with an exit code
 615 of 1.
 616 .PP
 617 When doing a comparison of files from a dump, an exit code of 2 indicates that
 618 some files were modified or deleted since the dump was made.
 619 .SH ENVIRONMENT
 620 If the following environment variable exists it will be utilized by
 621 .BR restore :
 622 .TP
 623 .B TAPE
 624 If no
 625 .B \-f
 626 option was specified,
 627 .B restore
 628 will use the device specified via
 629 .B TAPE
 630 as the dump device.
 631 .B TAPE
 632 may be of the form
 633 .IR tapename ,
 634 .I host:tapename
 635 or
 636 .IR user@host:tapename .
 637 .TP
 638 .B TMPDIR
 639 The directory given in
 640 .B TMPDIR
 641 will be used instead of
 642 .I /tmp
 643 to store temporary files.
 644 .TP
 645 .B RMT
 646 The environment variable
 647 .B RMT
 648 will be used to determine the pathname of the remote
 649 .BR rmt (8)
 650 program.
 651 .TP
 652 .B RSH
 653 .B Restore
 654 uses the contents of this variable to determine the name of the remote shell
 655 command to use when doing a network restore (rsh, ssh etc.). If this variable
 656 is not set,
 657 .BR rcmd (3)
 658 will be used, but only root will be able to do a network restore.
 659 .SH FILES
 660 .TP
 661 .I /dev/st0
 662 the default tape drive
 663 .TP
 664 .I /tmp/rstdir*
 665 file containing directories on the tape
 666 .TP
 667 .I /tmp/rstmode*
 668 owner, mode, and time stamps for directories
 669 .TP
 670 .I ./restoresymtable
 671 information passed between incremental restores
 672 .SH SEE ALSO
 673 .BR dump (8),
 674 .BR mount (8),
 675 .BR mke2fs (8),
 676 .BR rmt (8)
 677 .SH BUGS
 678 .B Restore
 679 can get confused when doing incremental restores from dumps that were made on
 680 active file systems.
 681 .PP
 682 A level 0 dump must be done after a full restore. Because
 683 .B restore
 684 runs in user code, it has no control over inode allocation; thus a full dump
 685 must be done to get a new set of directories reflecting the new inode
 686 numbering, even though the content of the files is unchanged.
 687 .PP
 688 The temporary files
 689 .I /tmp/rstdir*
 690 and
 691 .I /tmp/rstmode*
 692 are generated with a unique name based on the date of the dump and the process
 693 ID (see
 694 .BR mktemp (3) ),
 695 except when
 696 .B \-r
 697 or
 698 .B \-R
 699 is used. Because
 700 .B \-R
 701 allows you to restart a
 702 .B \-r
 703 operation that may have been interrupted, the temporary files should be the
 704 same across different processes. In all other cases, the files are unique
 705 because it is possible to have two different dumps started at the same time,
 706 and separate operations shouldn't conflict with each other.
 707 .PP
 708 To do a network restore, you have to run
 709 .B restore
 710 as root or use a remote shell replacement (see
 711 .B RSH
 712 variable).  This is due to the previous security history of
 713 .B dump
 714 and
 715 .BR restore .
 716 (
 717 .B restore
 718 is written to be setuid root, but we are not certain all bugs are gone from the
 719 code - run setuid at your own risk.)
 720 .PP
 721 At the end of restores in
 722 .B \-i
 723 or
 724 .B \-x
 725 modes (unless
 726 .B \-o
 727 option is in use),
 728 .B restore
 729 will ask the operator whether to set the permissions on the current
 730 directory. If the operator confirms this action, the permissions
 731 on the directory from where
 732 .B restore
 733 was launched will be replaced by the permissions on the dumped root
 734 inode. Although this behaviour is not really a bug, it has proven itself
 735 to be confusing for many users, so it is recommended to answer 'no',
 736 unless you're performing a full restore and you do want to restore the
 737 permissions on '/'.
 738 .PP
 739 It should be underlined that because it runs in user code,
 740 .B restore
 741 , when run with the
 742 .B \-C
 743 option, sees the files as the kernel presents them, whereas
 744 .B dump
 745 sees all the files on a given filesystem. In particular, this
 746 can cause some confusion when comparing a dumped filesystem a part
 747 of which is hidden by a filesystem mounted on top of it.
 748 .SH AUTHOR
 749 The
 750 .B dump/restore
 751 backup suite was ported to Linux's Second Extended File System by Remy Card
 752 <card@Linux.EU.Org>. He maintained the initial versions of
 753 .B dump
 754 (up and including 0.4b4, released in January 1997).
 755 .PP
 756 Starting with 0.4b5, the new maintainer is Stelian Pop <stelian@popies.net>.
 757 .SH AVAILABILITY
 758 The
 759 .B dump/restore
 760 backup suite is available from <http://dump.sourceforge.net>
 761 .SH HISTORY
 762 The
 763 .B restore
 764 command appeared in 4.2BSD.