Disk ARchive Publisher's description
from Denis Corbin
dar is a shell command that backs up directory trees and files.
dar is a shell command that backs up directory trees and files. It has been tested under Linux, Windows, Solaris, FreeBSD, NetBSD, MacOS X and several other systems, it is released under the GNU General Public License (GPL). Since version 2.0.0 an Application Interface (API) is available, opening the way for external/independent Graphical User Interfaces (GUIs) like kdar. This API relies on the libdar library, which is the core part of DAR programs; as such, the API is released under the GPL. Consequently, to use the API, your program must be released under the GPL as well.
dar is able to backup from total file system to a single file. Additionally a mechanism of filters permits, based on the filename, to exclude or include some files while backing up or restoring a directory tree. In the other side, a secondary filter mechanism permits to exclude some branches of a directory tree, or to only include some branches.
When making a backup with dar, you have the possibility to make a full backup or a differential backup. A full backup, as expected makes backup of all files as specified on the command line (with or without filters). Instead, a differential backup, (over filter mechanism), saves only files that have changed since a given reference backup. Additionally, files that existed in the reference backup and which do no more exist at the time of the differential backup are recorded in the backup. At recovery time, (unless you deactivate it), restoring a differential backup will update changed files and new files, but also remove files that have been recorded as deleted. Note that the reference backup can be a full backup or another differential backup. This way you can make a first full backup, then many differential backup, each taking as reference the last backup made.
Dar stands for Disk ARchive. From the beginning it was designed to be able to split an archive over several removable media whatever their number is and whatever their size is. Thus dar is able to save over old floppy disk, CD-R, DVD-R, CD-RW, DVD-RW, Zip, Jazz, etc... Dar is not concerned by un/mounting a removable medium, instead it is independent of hardware. Given the size, it will split the archive in several files (called SLICES), eventually pausing before creating the next one, allowing this way, the user to un/mount a medium, burn the file on CD-R, send it by email (if your mail system does not allow huge file in emails, dar can help you here also). By default, (no size specified), dar will make one slice whatever its size is. Additionally, the size of the first slice can be specified separately, if for example you want first to fulfill a partially filled disk before starting using empty ones. Last, at restoration time, dar will just pause and prompt the user asking a slice only if it is missing.
DIRECTORY TREE SNAPSHOT
Dar can make a snapshot of a directory tree and files recording the inode status of files. This may be used to detect changes in files "diffing" the resulting archive with the filesystem at a later time. The resulting archive can also be used as reference to save file that have changed since the snapshot has been done. A snapshot archive is very small compared to the corresponding full backup, but it cannot be used to restore any data.
dar can use compression. By default no compression is used. Actually only gzip and bzip2 algorithm are implemented, but some room has been made for any other compression algorithm. Note that, compression is made before slices, which means that using compression with slices, will not make slices smaller, but will probably make less slices in the backup.
even using compression dar has not to read the whole backup to extract one file. This way if you just want to restore one file from a huge backup, the process will be much faster than using tar. Dar first reads the catalogue (i.e. the contents of the backup), then it goes directly to the location of the saved file(s) you want to restore and proceed to restoration. In particular using slices dar will ask only for the slice(s) containing the file(s) to restore.
HARD LINK CONSIDERATION
hard links are now properly saved. They are properly restored if possible. If for example restoring across a mounted file system, hard linking will fail, but dar will then duplicate the inode and file content, issuing a warning.
What's New in This Release:В· fixed man pages in the NAME section: added whatis entry
В· fixed segfault: in the internal error reporting code (delete in
В· place of free())
В· fixed bug: dar_manager was not able to read properly the latest
В· generated databases version when having Extended Attributes recorded for
В· some files
В· avoided reporting unreleased memory block when compilation
В· optimization have been used (dar, dar_manager, dar_cp, dar_slave,
В· dar_xform do all reported unreleased memory when gcc optimization was
В· used in "infinint" mode)
System Requirements:No special requirements.
Program Release Status: Minor Update
Program Install Support: Install and Uninstall