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In reverse Polish notation, the operators follow their operands; for instance, to add 3 and 4, one would write 3 4 + rather than 3 + 4.
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restor(8) [bsd man page]

RESTOR(8)						      System Manager's Manual							 RESTOR(8)

NAME
restor - incremental file system restore SYNOPSIS
restor key [ argument ... ] DESCRIPTION
Restor is used to read magtapes dumped with the dump command. The key specifies what is to be done. Key is one of the characters rRxt optionally combined with f. f Use the first argument as the name of the tape instead of the default. r or R The tape is read and loaded into the file system specified in argument. This should not be done lightly (see below). If the key is R restor asks which tape of a multi volume set to start on. This allows restor to be interrupted and then restarted (an icheck -s must be done before restarting ). x Each file on the tape named by an argument is extracted. The file name has all `mount' prefixes removed; for example, /usr/bin/lpr is named /bin/lpr on the tape. The file extracted is placed in a file with a numeric name supplied by restor (actually the inode number). In order to keep the amount of tape read to a minimum, the following procedure is recommended: Mount volume 1 of the set of dump tapes. Type the restor command. Restor will announce whether or not it found the files, give the number it will name the file, and rewind the tape. It then asks you to `mount the desired tape volume'. Type the number of the volume you choose. On a multivolume dump the recom- mended procedure is to mount the last through the first volume in that order. Restor checks to see if any of the files requested are on the mounted tape (or a later tape, thus the reverse order) and doesn't read through the tape if no files are. If you are working with a single volume dump or the number of files being restored is large, respond to the query with `1' and restor will read the tapes in sequential order. If you have a hierarchy to restore you can use dumpdir(8) to produce the list of names and a shell script to move the resulting files to their homes. t Print the date the tape was written and the date the file system was dumped from. The r option should only be used to restore a complete dump tape onto a clear file system or to restore an incremental dump tape onto this. Thus mkfs /dev/hp0a 4807 restor r /dev/hp0a is a typical sequence to restore a complete dump. Another restor can be done to get an incremental dump in on top of this. A dump followed by a mkfs and a restor is used to change the size of a file system. FILES
/dev/rmt1 default file name rst* temporary files SEE ALSO
dump(8), dumpdir(8), mkfs(8) DIAGNOSTICS
There are various diagnostics involved with reading the tape and writing the disk. There are also diagnostics if the i-list or the free list of the file system is not large enough to hold the dump. If the dump extends over more than one tape, it may ask you to change tapes. Reply with a newline when the next tape has been mounted. Dump tapes made before the new ondisc directory structure will be converted automatically by restor . BUGS
There is redundant information on the tape that could be used in case of tape reading problems. Unfortunately, restor does't use it. 3rd Berkeley Distribution RESTOR(8)

Check Out this Related Man Page

DUMP(5) 							File Formats Manual							   DUMP(5)

NAME
dump, ddate - incremental dump format SYNOPSIS
#include <sys/types.h> #include <sys/ino.h> #include <dumprestor.h> DESCRIPTION
Tapes used by dump and restor(8) contain: a header record two groups of bit map records a group of records describing directories a group of records describing files The format of the header record and of the first record of each description as given in the include file <dumprestor.h> is: #if UCB_NKB == 1 #define NTREC 10 #endif #ifndef UCB_NKB #define NTREC 20 #endif #define MLEN 16 #define MSIZ 4096 #define TS_TAPE 1 #define TS_INODE 2 #define TS_BITS 3 #define TS_ADDR 4 #define TS_END 5 #define TS_CLRI 6 #define MAGIC (int)60011 #define CHECKSUM (int)84446 struct spcl { int c_type; time_t c_date; time_t c_ddate; int c_volume; daddr_t c_tapea; ino_t c_inumber; int c_magic; int c_checksum; struct dinodec_dinode; int c_count; char c_addr[BSIZE]; } spcl; struct idates { char id_name[16]; char id_incno; time_t id_ddate; }; NTREC is the number of BSIZE (sys/param.h) byte records in a physical tape block. MLEN is the number of bits in a bit map word. MSIZ is the number of bit map words. The TS_ entries are used in the c_type field to indicate what sort of header this is. The types and their meanings are as follows: TS_TAPE Tape volume label TS_INODE A file or directory follows. The c_dinode field is a copy of the disk inode and contains bits telling what sort of file this is. TS_BITS A bit map follows. This bit map has a one bit for each inode that was dumped. TS_ADDR A subrecord of a file description. See c_addr below. TS_END End of tape record. TS_CLRI A bit map follows. This bit map contains a zero bit for all inodes that were empty on the file system when dumped. MAGIC All header records have this number in c_magic. CHECKSUM Header records checksum to this value. The fields of the header structure are as follows: c_type The type of the header. c_date The date the dump was taken. c_ddate The date the file system was dumped from. c_volume The current volume number of the dump. c_tapea The current number of this (512-byte) record. c_inumber The number of the inode being dumped if this is of type TS_INODE. c_magic This contains the value MAGIC above, truncated as needed. c_checksum This contains whatever value is needed to make the record sum to CHECKSUM. c_dinode This is a copy of the inode as it appears on the file system; see filsys(5). c_count The count of characters in c_addr. c_addr An array of characters describing the blocks of the dumped file. A character is zero if the block associated with that character was not present on the file system, otherwise the character is non-zero. If the block was not present on the file system, no block was dumped; the block will be restored as a hole in the file. If there is not sufficient space in this record to describe all of the blocks in a file, TS_ADDR records will be scattered through the file, each one picking up where the last left off. Each volume except the last ends with a tapemark (read as an end of file). The last volume ends with a TS_END record and then the tape- mark. The structure idates describes an entry of the file /etc/ddate where dump history is kept. The fields of the structure are: id_name The dumped file system is `/dev/id_nam'. id_incno The level number of the dump tape; see dump(8). id_ddate The date of the incremental dump in system format see types(5). FILES
/etc/ddate SEE ALSO
filsys(5), types(5), dump(8), dumpdir(8), restor(8) 3rd Berkeley Distribution DUMP(5)

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