bextract

Normally, you will restore files by running a Restore Job from the Console program. However, bextract can be used to extract a single file or a list of files from a Bacula tape or file. In fact, bextract can be a useful tool to restore files to an empty system assuming you are able to boot, you have statically linked bextract and you have an appropriate bootstrap file.

Some of the current limitations of bextract are:

It cannot restore access control lists (ACL) that have been backed up along with the file data.
It cannot restore encrypted files.
The command line length is relatively limited, which means that you cannot enter a huge number of volumes. If you need to enter more volumes than the command line supports, please use a bootstrap file (see below).

It is called:

Usage: bextract [-d debug_level] <device-name> <directory-to-store-files>
-b <file> specify a bootstrap file
-c <file> specify a Storage configuration file
-dnn set debug level to nn
-dt print timestamp in debug output
-T send debug traces to trace file
-e <file> exclude list
-i <file> include list
-p proceed inspite of I/O errors
-t read data from volume, do not write anything
-v verbose
-V specify Volume names (separated by |)
-? print this message

where device-name is the Archive Device (raw device name or full filename) of the device to be read, and directory-to-store-files is a path prefix to prepend to all the files restored.

Note

On Windows systems, if you specify a prefix of say d:/tmp, any file that would have been restored to c:/My Documents will be restored to d:/tmp/My Documents. That is, the original drive specification will be stripped. If no prefix is specified, the file will be restored to the original drive.

Extracting with Include or Exclude Lists

Using the -e option, you can specify a file containing a list of files to be excluded. Wildcards can be used in the exclusion list. This option will normally be used in conjunction with the -i option (see below). Both the -e and the -i options may be specified at the same time as the -b option. The bootstrap filters will be applied first, then the include list, then the exclude list.

Likewise, and probably more importantly, with the -i option, you can specify a file that contains a list (one file per line) of files and directories to include to be restored. The list must contain the full filename with the path. If you specify a path name only, all files and subdirectories of that path will be restored. If you specify a line containing only the filename (e.g. my-file.txt) it probably will not be extracted because you have not specified the full path.

For example, if the file include-list contains:

/home/kern/bacula
/usr/local/bin

Then the command:

./bextract -i include-list -V Volume /dev/nst0 /tmp

will restore from the Bacula archive /dev/nst0 all files and directories in the backup from /home/kern/bacula and from /usr/local/bin. The restored files will be placed in a file of the original name under the directory /tmp (i.e. /tmp/home/kern/bacula/... and /tmp/usr/local/bin/...).

Extracting With Bootstrap File

The -b option is used to specify a bootstrap file containing the information needed to restore precisely the files you want. Specifying a bootstrap file is optional but recommended because it gives you the most control over which files will be restored. For more details on the bootstrap file, please see Restoring Files with the Bootstrap File chapter of this document. Note, you may also use a bootstrap file produced by the restore command. For example:

./bextract -b bootstrap-file /dev/nst0 /tmp

The bootstrap file allows detailed specification of what files you want restored (extracted). You may specify a bootstrap file and include and/or exclude files at the same time. The bootstrap conditions will first be applied, and then each file record seen will be compared to the include and exclude lists.

Extracting From Multiple Volumes

If you wish to extract files that span several Volumes, you can specify the Volume names in the bootstrap file or you may specify the Volume names on the command line by separating them with a vertical bar. See the section above under the bls program entitled Listing Multiple Volumes for more information. The same techniques apply equally well to the bextract program or read the Bootstrap chapter of this document.

Test Extraction

If you wish to ensure that all blocks of a volume are valid, you can specify the -t flag. A bootstrap might be used with this option. It is also possible to setup and use a Verify Job.