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Дата изменения: Sun May 4 15:24:41 1997
Дата индексирования: Mon Oct 1 22:50:53 2012
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Restoring files with tar next up previous contents index
Next: Multilevel backups Up: Simple backups Previous: Making backups with tar

 

Restoring files with tar

The -extract (-x) option for tar  extracts files:

# tar -extract -same-permissions -verbose -file /dev/fd0H1440
usr/src/
usr/src/linux
usr/src/linux-1.2.10-includes/
usr/src/linux-1.2.10-includes/include/
usr/src/linux-1.2.10-includes/include/linux/
usr/src/linux-1.2.10-includes/include/linux/hdreg.h
usr/src/linux-1.2.10-includes/include/linux/kernel.h
...
#
You also extract only specific files or directories (which includes all their files and subdirectories) by naming on the command line:
# tar xpvf /dev/fd0H1440 usr/src/linux-1.2.10-includes/include/linux/hdreg.h
usr/src/linux-1.2.10-includes/include/linux/hdreg.h
#
Use the -list (-t) option, if you just want to see what files are on a backup volume:
# tar -list -file /dev/fd0H1440
usr/src/
usr/src/linux
usr/src/linux-1.2.10-includes/
usr/src/linux-1.2.10-includes/include/
usr/src/linux-1.2.10-includes/include/linux/
usr/src/linux-1.2.10-includes/include/linux/hdreg.h
usr/src/linux-1.2.10-includes/include/linux/kernel.h
...
#
Note that tar  always reads the backup volume sequentially, so for large volumes it is rather slow. It is not possible, however, to use random access database techniques when using a tape drive or some other sequential medium.

tar  doesn't handle deleted files properly. If you need to restore a filesystem from a full and an incremental backup, and you have deleted a file between the two backups, it will exist again after you have done the restore. This can be a big problem, if the file has sensitive data that should no longer be available.



Lars Wirzenius
Sun May 4 14:08:43 EEST 1997