1:dar

From Linux Man Pages

      dar - disk archive

dar can store a backup in several files (called "slices" in the following) of a given size, eventually pausing or
running a user command/script before starting the next slice. This can allow for example, the burning of the last
generated slice on a CD-R, or changing a floppy disk before continuing on the next one. Like its grand-brother,
the great "tar" command, dar may also use compression, at the difference that compression is used inside the
archive to be able to have compressed slices of the defined size. But the most important feature of dar is its
ability to make differential backups. In other words, backups that contain only new files or files that have
changed from a backup of reference. Moreover with differential backup, dar also stores files that have been
deleted since the backup of reference. Thus, when restoring, first a full backup, then additional differential
backups, at each restoration you get the exact state of the filesystem at the time of the backup. And of course,
the reference backup may be a full or a differential backup itself.

dar is the first backup program I know that can also remove files during restoration! By the way, in this docu-
ment, "archive" and "backup" design the same thing, and are used interchangeably.

At the difference of the tar command, dar is not suited to directly use tapes. So keep using tar for tape
archives. Because, even using tar to write a slice on a tape, you will loose all the interest of another feature
of dar which is its ability to directly access the data of saved file even when compression is used. This way and
in contrast to the tar command, dar is able to extract a given file much faster from a backup and to also recover
files that follow a data corruption (loosing just the file in which data corruption occurred).

This has of course its limitations, in particular when a data corruption occurs in the vital part of the backup,
i.e. the few first bytes of each slice, and the last part of the archive (the catalogue). In case you need to
store archive on a bad quality medium, you could protect each slice with a Parchive recovery file. (see NOTES for
more information about Parchive, and how to transparently run Parchive from dar)

Slices have a base name given on the command line, which is completed by a dot, a number, a dot and the extension
(dar) to form a filename. On command line you will never have to give the full file name of a slice.

Let's take an example :

considering the base name "joe", dar will make one or several slices during backup.
Theses are files with the names joe.1.dar joe.2.dar ... joe.10.dar ... etc. If you
want to extract, list, or use these backup as reference, you will only have to use the
base name which is the string "joe" here.

OPTIONS

COMMANDS :

Important note: Not all system actually support long options (Solaris, FreeBSD, ...). For example --create will
not be available on theses systems, and you will have to use -c instead. In the same way, not all system do sup-
port optional arguments (FreeBSD without GNU getopt for example), you then need to explicitly give the argument,
for example in place of "-z" you will need to give "-z 9", see "EXPLICIT OPTIONAL ARGUMENTS" paragraph near the
end of this document.

-c, --create [<path>/]<basename>
creates a backup with the name based on <basename>. All the slices will be created in
the directory <path> if specified, else in the current directory. If the destination
filesystem is too small to contain all the slices of the backup, the -p option (paus-
ing before starting new slices) might be of interest. Else, in the case the filesystem
is full, dar will suspend the operation, asking for the user to make free space, then
continue its operation. To make free space, the only thing you cannot do is to touch
the slice being written. If the filename is "-" *and* no slice is asked for (no -s)
the archive is produced on the standard output.

-x, --extract [<path>/]<basename>
extracts files from the given backup. Slices are expected to be in the current direc-
tory or in the directory given by <path>. It is also possible to use symbolic links to
gather slices that are not in the same directory. Path may also point to a removable
device (floppy, CD, etc.), in this case, to be able to mount/unmount the device, you
must not launch dar from that directory. In other words, the current directory must
not be that directory (see tutorial for details).

-l, --list [<path>/]<basename>
lists the contents of the given backup. In general dar will only require the first and
the last slice of the archive.

-t, --test [<path>/]<basename>
checks the backup integrity. Even without compression, dar is able to detect at least
one error by data file, thanks to a 16 bits CRC recorded in the catalogue. If one
error occurred in file's data stored the archive, dar will report it in 100% of all
cases. If two error occurred, dar will see them in 93,8% of all cases. If three error
occurred, dar will see them in 100% of all cases. If four errors occurred, dar will
see them in 90.6% of all cases, etc.

-d, --diff [<path>/]<basename>
compares saved files in the backup with those in the filesystem.

-C, --isolate [<path>/]<basename>
isolate a catalogue from its archive. The argument is the basename of the file that
will contain the catalogue. The -A option is mandatory here to give the name of the
archive to extract the catalogue from. Slicing is available (-s -S -p -b etc.). If the
filename is "-" *and* no slice is asked (no -s) the catalogue is produced on the stan-
dard output, allowing to send the resulting catalogue through a pipe. Note that there
is no difference in concept between a catalogue and an archive. Thus you can do all
operation on a catalogue, in particular take it as reference for a differential
archive. A catalogue produced with -C is just like a differential archive done right
after a full backup, (no data in it).

-h, --help displays help usage.

-V, --version displays version information.

GENERAL OPTIONS:

-v, --verbose verbose output

-b, --beep makes the terminal ring when user action is required (like for example the creation of
a new slice using the -p option)

-n, --no-overwrite do not allow overwriting of any file or slice.

-w, --no-warn Do not warn before overwriting file or slice. By default (no -n and no -w) overwriting
is allowed but a warning is issued before proceeding. This option may receive 'a' as
argument:

-wa, --no-warn=all This implies the -w option, and means that over avoiding warning for file overwriting,
DAR also avoid signaling a file about to be removed when its type is not the expected
one. File are removed when they have been recorded as deleted since the archive of
reference. At restoration of the differential archive, if a file of the given name
exists, it is remove, but if the type does not match the file that was present at the
time of the archive of reference (directory, plain file, fifo, socket, char or block
device, etc.), a warning is normally issued to prevent the accidental removal of data
that was not saved in the backup of reference. (See also -k option)

-R, --fs-root <path>
The path points to the directory tree containing all the files that will be enrolled
in the operation (backup or restoration). By default the current directory is used.
All other paths used in -P or -g options on the command line are and must be relative
to this path (or to current directory if -R is not present).

-X, --exclude <mask>
The mask is a string with wild cards (like * and ?) which is applied to filenames
which are not directories. If a given file matches the mask, it is excluded from the
operation. By default (no -X on the command line), no file is excluded from the opera-
tion. -X may be present several times on the command line, in that case a file will
not be considered for the given operation if it matches at least one -X mask.

-I, --include <mask>
The mask is applied to filenames which are not directories. If a given file matches
the mask and does not match any mask given with -X, the file is selected for the oper-
ation. By default (no -I and no -X on the command line), all files are included for
the operation. -I may be present several times on the command line, in that case all
file that match one of the -I mask will be considered for the given operation, if they
do not also match one of the -X mask.

-P, --prune <path> Do not consider file or directory sub-tree given by the path. -P may be present sev-
eral time on the command line. The difference with -X is that the mask is not applied
only to the filename, but also include the path. Moreover it applies also to directo-
ries (-X does not). By default (no -P on the command-line), no sub-tree or file is
excluded from the operation, and all the directory tree (as indicated by -Roption) is
considered. Note that <path> may contains wild-cards like * or ? see glob(7) man page
for more informations.

-g, --go-into <path>
Files or directory to only take in account, as opposed to -P. -g may be present sev-
eral time on command-line. Same thing here, the difference with -I is that the mask is
applied to the path+filename and also concerns directories. By default all files under
the -R directory are considered. Else, if one or more -g option is given, just those
are selected (if they do not match any -P option). All paths given this way must be
relative to the -R directory. This is equivalent as giving <path> out of any option.
All theses out of option arguments are also referred as [list of paths]. Warning, -g
option cannot receive wild-cards (nor [list of paths]), they will not be interpreted.

File selection in brief:

As seen above, -I -X -P and -g options are used to select the files to operate on. -I and -X only use the
filename of files and do not apply to directories, while -P and -g use the filename *and* the path, they
*do* apply to directories.

since version 2.2.0 two modes of interpretation of theses options exist. The normal original method and
the ordered method:

the normal method is the default:
A directory is elected for operation if no -P option excludes it. If at least one -g option is
given one command line, one -g option must cover it, else it is not elected for operation. If
a directory is not selected, no recursion is done in it (the directory is pruned). For non
directories files, the same is true (P and -g do apply) and a second test must also be satis-
fied: no -X option must exclude the filename, and if at least one -I option is given, one must
match the given filename (using or not wild-cards).

the ordered method (when -am option is given on command-line):
The ordered method takes care of the order of presence between -X and -I on one hand and of -P
and -g in the other hand. In the ordered method the last argument take precedence on all the
previous ones, let's take an example:

-X "*.mp?" -I "*.mp3" -I "toto*"
Here dar will include all files except file of name "*.mp?" (those ending with "mpX"
where X is any character), but it will however include those ending with "mp3". It will
also include files which name begin by "toto" whatever they end with. This way,
"toto.mp2" will be saved (it begins by "toto") as well as "titi.txt" as well as "joe.mp3"
(it ends by "mp3"). But will not be saved "joe.mp2" (because it does not begin by "toto",
nor ends by "mp3", and match "*.mp?" mask). As we see the last option (-I or -X) over-
comes the previous one. -P and -g act the same but as seen above they do not act on file-
name only, but on the whole path+filename. Note that (-g , -P) and (-X , -I) are indepen-
dent concerning their relative order. You can mix -X -I -g -P in any order, what will be
important is the relative positions of -X options compared to -I options, and the rela-
tive positions of -g options relatively to -P options.

In logical terms, if <prev_mask> is the mask generated by all previous mask on the command line, -I
<mask> generates the new following mask: <prev_mask> or <mask> . While -X <mask> generates the new
following mask: <prev_mask> and not <mask>. This is recursive each time you add a -I or -X option.
Things work the same with -P and -g options.

-g option has been said to be equivalent to [list of paths]. This is true in the normal method, but
false using the ordered method. Argument given in [list of paths] are usually moved after any other
options, so they loose their relative position regarding -P options. In the ordered method this is
annoying, thus -g option has been created to overcome this getopt() system call behavior.
This ends the file selection explication let's continue with other options.

-u, --no-user-EA Do not consider the Extended Attributes (EA) of the user namespace. By default, they
are saved and restored, if the support for EA has been activated at compilation time.
If not, this option is forced internally (you need not specify it).

-U, --no-system-EA Do not consider the EA of the root (or system) namespace. By default, they are saved
and restored, if the support for EA has been activated at compilation time. If not,
this option is forced internally (you need not specify it).

Note concerning Extended Attributes (EA)

Support for EA must be activated at compilation time (the configure script tries to do so if your system
has all the required support for that). Thus you can get two binaries of dar (of the same version), one
supporting EA and another which does not (dar -V to see whether EA support is activated). The archives
they produce are the same and can be read by each other. The only difference is that the binary without EA
support is not able to save or restore EAs, but is still able to test them and list their presence.

-i, --input <path> is available when reading from pipe (basename is "-" for -x, -l, -t, -d or for -A when
-c or -C is used). When reading from pipe, standard input is used, but with this
option, the file <path> (usually a named pipe) is used instead. This option is to
receive output from dar_slave program (see doc/NOTES for examples of use).

-o, --output <path> is available when reading from pipe (basename is "-" for -x, -l, -t, -d or for -A when
-c or -C is used). When reading from pipe, standard output is used to send request to
dar_slave, but with this option, the file <path> (usually a named pipe) is used
instead. When standard output is used, all messages goes to standard error (not only
interactive messages). See doc/NOTES for examples of use.

-O, --ignore-owner Do not consider user ID (uid) or group ID (gid), when comparing with archive of refer-
ence (-c -A) while doing a differential backup, when extracting (-x) or when comparing
(-d). This is useful when dar is used by a non-privileged user. It will not consider a
file has changed just because it has only the uid or gid changed, nor report a compar-
ison mismatch if only uid or gid is different.

-H[num], --hour[=num]
if -H is used, two dates are considered equal if they differ from a integer number of
hours, and that number is less than or equal to [num]. If not specified num defaults
to 1. This is used when making a differential backup, to compare last_modification
date of inodes, and at restoration time if the -r option (restore only more recent
files) is used. This is to workaround some filesystems (like Samba filesystem) that
seems to change the dates of files after having gone from or to daylight saving time
(winter/summer time).

-E, --execute <string>
the string is a user command-line to be launched between slices. For reading (thus
using -t, -d, -l or -x options), the command is executed before the slice is read or
even asked, for writing, (thus using -c or -C option), the command is executed once
the slice has been completed. Some substitution string can be used in the string:

%% will be replaced by %

%p will be replaced by the slice path

%b will be replaced by the slice basename

%n will be replaced by the slice number (to be read or just written). For read-
ing, dar often needs the last slice, but initially it does not know its num-
ber. If it cannot be found in the current directory, the user command-line
is then called with %n equal to 0. This is a convenient way to inform the
user command to provide the last slice. If after it is still not present,
dar asks the user (as usually) with a message on the terminal. Once the last
slice is found, the user command-line is called a second time, with %n equal
to the value of the last slice number.

%e will be replaced by the slice extension (always substituted by "dar")

%c will be replaced by the context. Actually two possible value exist: "init"
and "operation". When reading an archive for (testing, extraction, diff,
listing, or while reading the archive of reference, see below the -F
option), the "init" context takes place from the beginning up to the time
the catalogue is retrieved. On a multiple slice archive this correspond to
the first slice request and to the last slice requests. After, that point
comes the "operation" context. While creating an archive, the context is
always "operation".
Several -E option can be given, given commands will then be called in the order they appear on the command
line, and included files.

-F, --execute-ref <string>
same as -E but is applied between slices of the reference archive (-A option).

-K, --key [[<algo>]:]<string>
encrypt/decrypt the archive using the <algo> cypher with the <string> as pass phrase.
An encrypted archive can only be read if the same pass phrase is given. Available
cyphers are "blowfish" (alias "bf") for strong encryption and "scrambling" (alias
"scram") for a very weak encryption. By default if no <algo> or no ':' is given, the
blowfish cypher is assumed. If your password contains a column ':' you need to specify
the cypher to use (or at least use the initial ':' which is equivalent to 'bf:'). If
the <string> is empty the pass phrase will be asked at execution time. Thus, the
smallest argument that -K can receive is ':' which means blowfish cypher with the pass
phrase asked at execution time.

-J, --key-ref [[<algo>]:]<string>
same as -K but the given key is used to decrypt the archive of reference (given with
-A option).

-#, --crypto-block <size>
to be able to randomly access data in an archive, it is not encrypted globally but
block by block. You can define the encryption block size thanks to this argument which
default to 10240 bytes. Note that syntax used for -s option is also available here.
Note also that crypto-block is stored as a 32 bits integer thus value larger than 4GB
will cause an error.

-*, --crypto-block-ref <size>
same as --crypto-block but for the archive of reference (same default value).

-B, --batch <filename>
You can put in the file any option or argument as used on command line, that will be
parsed as if they were in place of the "-B <filename>" option. This way you can over-
come the command line size limitation. Commands in the file may be disposed on several
lines, and -B option can also be used inside files, leading a file to include other
files. But an error occurs in case of loop (a file includes itself) and DAR aborts
immediately. Comments are now allowed, and must start by a hash `#' character on each
line. Note that for a line to be considered as comment the hash character must be the
first character of the line (space or tab can still precede the hash). See Conditional
Syntax bellow for a more rich syntax in configuration files.

-N, --noconf Do not try to read neither ~/.darrc nor /etc/darrc configuration files. See files sec-
tion bellow.

-e, --empty Do not perform any action (backup or restoration), displays all messages as if it was
for real ("dry run" action).

-aSI, --alter=SI[-unit[s]]
when using k M G T E Z Y prefixes to define a size, use the SI meaning: multiple of
10^3 (a Mega is 1,000,000).

-abinary, --alter=binary[-unit[s]]
when using k M G T E Z Y prefixes to define a size, use the historical computer sci-
ence meaning: multiple of 2^10 (a Mega is 1,048,576).

--alter=SI and --alter=binary can be used several times, they affect all prefix which follow even those
found in file included by -B option up to the next --alter=... occurrence. Note that if in a file included
by -B option an --alter=binary or --alter=SI is met, it affects all the following prefix even those out-
side the included files (for example in the following "-B some.dcf -s 1K" 1K may be equal to 1000 or 1024
depending on the presence of an --alter=SI or --alter=binary in the file some.dcf. By default (before any
--alter=SI/binary argument has been reached), binary interpretation of suffix is done (for compatibility
with older versions).

-Q Do not display initial warning on stderr when not launched from a terminal (for exam-
ple when launched from an at job or crontab). Remains that any question to the user
will be assumed a 'no' answer, which most of the time will abort the program. Impor-
tant, this option cannot be used inside configuration files (see -B option), it must
be present on the command line. Since version 2.2.2, giving this option on command-
line also forces the non interactive mode even if dar is launched from terminal, this
makes dar possible to run in background (it is recommended to then redirect the stdout
and/or stderr to some files).

-aa, --alter=atime when reading a filesystem, while doing a backup (-c option) or comparing (-d option)
by default dar tries to be as much transparent as possible, and set back the last
access time (atime) of read files and directories, as if they have not been read. But,
preserving atime of read files, make their ctime to be changed (last inode change).
There is no possibility to preserve both atime and ctime. If you want to overcome the
default original behavior of dar and want to keep ctime unchanged, the --alter=atime
is for you. Some security software rely on the ctime to be preserved, some other soft-
ware rely on the atime to be preserved like leafnode NNTP caching software.

-ac, --alter=ctime set back the date alteration to ctime (see --alter=atime above), this is the default
behavior. The use of this switch is to override the -aa option in dar configuration
files or command-line (see -B option). From -aa and -ac the one which is last parsed
from command-line or included files takes the win.

-am, --alter=mask set the ordered mode for mask. This affects the way -I and -X options are interpreted,
as well as -g and -P options, and -Z and -Y options. It can take any place on the com-
mand-line and can be placed only once.

-an, --alter=no-case
set the filters in case insensitive mode. This concerns only masks specified after
this option (see also -acase option below). This changes the behavior of -I, -X, -g,
-P, -Z and -Y options.

-acase, --alter=case
set back to case sensitive mode for filters. All following masks are case insensitive,
up to end of parsing or up to the next -an option. This changes the behavior of -I,
-X, -g, -P, -Z and -Y options.

-j, --jog when virtual memory is exhausted, ask user to make room before trying to continue. By
default, when memory is exhausted dar aborts.

SAVING AND ISOLATION OPTIONS (to use with -c or -C)

-z[level], --gzip[=level]
compresses within slices using gzip algorithm (if not specified, no compression is
performed). The compression level (an integer from 1 to 9) is optional. -z is
equivalent to -z9 which is max compression/slow processing. At the opposite, 1 means
less compression and faster processing.

-y[level], --bzip2[=level]
compresses using bzip2 algorithm. See -z above for usage details.

-s, --slice <number>
Size of the slices in bytes. If the number is appended by k (or K), M, G, T, P E, Z or
Y the size is in kilobytes, megabytes, gigabytes, terabytes, petabytes, exabytes,
zettabytes or yottabytes respectively. Example: "20M" means 20 megabytes, by default,
it is the same as giving 20971520 as argument (see also -aSI and -abinary options). If
-s is not present the backup will be written to a single slice whatever the size of
the backup may be (there is probably some filesystem limitation, thus you might expect
problems for file size over 2 gigabytes, depending on your filesystem, but this is not
a limitation of dar).

-S, --first-slice <number>
-S gives the size of the first slice which may be chosen independently of the size of
following slices. This option needs -s and by default, the size of the first slice is
the same as the one of the following slices.

-p, --pause pauses before writing to a new slice (this requires -s). By default there is no pause,
all slices are written in the same directory, up to the end of the backup or until the
filesystem is full. In this later case, the user is informed of the lack of disk space
and dar stops for user action. As soon as some disk space is available, the user can
continue the backup.

-A, --ref [<path>]/<basename>
specifies the archive to use as reference (mandatory with -C). By default no archive
is used and all files are saved (in regards to -I -X -P and -g options). All slices of
the reference backup are expected to be on the same directory given by <path> or the
current directory by default. Usually only the first and the last slice are required
to extract the catalogue of reference and the use of symbolic links is also possible
here to gather slices that do not reside in the same directory. You can also point
<path> to a floppy or any other mounted directory, because dar will pause and ask the
user for required slices if they are not present.

-D, --empty-dir When excluding directories either explicitly using -P option, or implicitly by giving
a -g option dar does not store anything about theses. But with -D option, dar stores
them as empty directories. This can be useful, if excluding a mount point (like /proc
or /dev/pts). At restoration time, dar will then recreate theses directories (if nec-
essary). This option has no meaning with -C and is ignored in that case.

-Z, --exclude-compression <mask>
Filenames covered by this mask are not compressed. It is only useful with -z or -y. By
default, all file are compressed (if compression is used). This option can be used
several times, in that case a file that matches one of the -Z mask will not be com-
pressed.

-Y, --include-compression <mask>
Filenames covered by this mask (and not covered by -Z) are the only to be compressed.
It is only available with -z no -y. By default all files are compressed. This option
can be used several times, in that case all files that match one of the -Y will be
compressed, if they do not also match on of the -Z masks. The ordered method here
applies too when activated (with -am option), it works exactly the same as -I and -X
options, but apply to file compression, not file selection.

-m, --mincompr <number>
files which size is below this value will not be compressed. If -m is not specified it
is equivalent to giving -m 100 as argument. If you want to compress all file whatever
their size is you thus need to type -m 0 on the command line. The same number exten-
sions as those used with -s or -S are available here, if you want to specify the size
in kilobyte, megabyte, gigabyte etc.

--nodump do not save files which have the 'd' flag set (see chattr(1) lsattr(1) ext2 commands).
This option may not be available if the system dar has been compiled on did not pro-
vide support for ext2 flags.

-G, --on-fly-isolate [<path>]/<basename>
When creating a backup, perform a catalogue isolation of the resulting archive. This
step is done after the backup has completed. The on-fly isolation is compressed with
bzip2 (using compression level 9), and is a single sliced archive without encryption.
Due to command-line exiguity, it is not possible to change compression algo, slice
size or encryption scheme for the on-fly isolation. If you need a more complicated
thing, either look for a GUI over libdar, or do a normal isolation (By the way it is
possible to isolate an already isolated catalogue, this is equivalent to a copy, but
you can add encryption, change compression, change slicing, etc.), you can also use
dar_xform if you only want to change slices size (this is faster as no decompres-
sion/re-compression is done).

-M, --no-mount-points
stay in the same filesystem as the root directory (see -R option), subdirectory that
are mounting points for other filesystems will not be saved or saved empty if -D
option is used.

RESTORATION OPTIONS (to use with -x)

-k, --no-deleted Do not delete files that have been deleted since the backup of reference (file over-
writing can still occur). By default, files that have been destroyed since the backup
of reference are deleted during restoration, but a warning is issued before proceed-
ing, except if -w is used. If -n is used, no file will be deleted (nor overwritten),
thus -k is useless when using -n.

-r, --recent restore only files that are absent or more recent than those present in filesystem. -r
is useless if -n is present.

-f, --flat do not restore directory structure. All file will be restored in the directory given
to -R, if two files of the same name have to be restored, the usual scheme for warning
(-w option) and overwriting (-n option) is used. No rename scheme is planned actually.
When this option is set, dar does not remove files that have been stored as deleted
since last backup. (-f implicitly implies -k).

TESTING AND DIFFERENCE OPTIONS (to use with -t or -d)

No specific option, but all general options are available except -n and -w which are useless, as testing
and comparing only read data.

LISTING OPTIONS (to use with -l)

-T, --tar-format can be used to have a listing that displays the tree structure.

-as, --alter=saved list only saved files

-I and -X can be used to filter file to list base on their name. With -T the tree structure is
not filtered unlike without -T. Note that -P and -g options are not available while
listing.

Else only -v and -b from general options are useful. Note that -v displays an archive summary first, where
a lot of information about the archive can be obtained.

displayed fields

[data] possible values are [ ] or [Saved] or [InRef] . [ ] means that the data has
not been saved because there is no change since backup of reference. [Saved] means
that the data has been saved, and thus this archive is able to restore the file.
[InRef] is used when isolating a catalogue from an archive, and means the file was
saved in the reference archive.

[EA] possible values are " " (empty string) or [Saved] or [ ]. It Shows if Extended
Attributes are present and saved ([Saved]), are present but not saved ([ ]) which
means there is no change since backup of reference, or if there is no EA saved for
this file (empty string).

[compr] possible values are [....%] or [-----] or [ ] or [worse]. Shows if the file has
been compressed and the compression rate reached ([...%]), or if the file is stored
without compression ([ ] see -Y and -Z options) or if the file is not subject to
compression because it is not a saved regular file ([----]), or if the file takes more
space compressed than its original size ([worse]), due to compression overhead.

permission
see ls man page

user owner of the file

group group owner of the file

size size in byte of the file (if compression is enabled, the real size in the archive is
"compression rate" time smaller).

date the last modification date of the file. The last access time is also saved and
restored, but not displayed.

filename The name of the file.

EXPLICIT OPTIONAL ARGUMENTS

      When dar has not been compiled with GNU getopt, which is not present by default on some systems like FreeBSD, you
      may lack the optional arguments syntax. For example "-z" will create a parse error on command-line, or in -B con-
      figuration files. The solution is to explicitly give the argument. Here follows a list of  explicit  argument  to
      use in place of optional ones:
 
      -z                  must be replaced by -z 9
 
      -y                  must be replaced by -y 9
 
      -w                  must be replaced by -w d or -w default
 
      -H                  must be replaced by -H 1
 
      important  !   When  using  GNU  getopt(), optional arguments are available by sticking the argument to the short
      option: "-z" for example is available as well as "-z9". But "-z 9" is wrong, it will be read as "-z"  option  and
      "9" as member of [list of path]. In the other side, when using a non GNU getopt this time, "-z" becomes an option
      that always requires an argument, and thus "-z 9" is read as "-z" option with "9" as argument, while  "-z9"  will
      be  rejected  as  a  unknown  option, and "-z" alone will generate an error as no argument is provided. In conse-
      quences, you need a space between the option (like "-z") and its argument (like "9"), when dar does not rely on a
      GNU getopt() call, which also imply you to explicitly use arguments to options listed just above.

EXIT CODES

dar exits with the following code:

0 Operation successful.

1 Syntax error on command-line.

2 Error due to a hardware problem or a lack of memory.

3 Detection of a condition that should never happen, and which is considered as a bug of the application.

4 Code issued when the user has aborted the program upon dar question from dar. This also happens when
dar is not run from a terminal (for example launched from crontab) and dar has a question to the user.
In that case, dar aborts the same way as if the user pressed the escape key at the question prompt.

5 is returned when an error concerning the treated data has been detected. While saving, this is the case
when a file could not be opened or read. While restoring, it is the case when a file could not be cre-
ated or replaced. While comparing, it is the case when a file in the archive does not match the one in
the filesystem. While testing, it is the case when a file is corrupted in the archive.

6 an error occurred while executing user command (given with -E or -F option). Mainly because the cre-
ation of a new process is not possible (process table is full) or the user command returned an error
code (exit status different of zero).

7 an error has occurred when calling a libdar routine. This means the caller (dar program), did not
respect the specification of the API (and this can be considered as a particular case of a bug.

8 the version used of dar is based in finite length integers (it has been compiled with the option
--enable-mode=...). This code is returned when an integer overflow occurred. use the full version
(based in infinint) to avoid this error.

9 this code indicates an unknown error. I have probably forgotten to update the exception caching code to
take care of new exceptions... this is a minor bug you are welcome to report.

10 you have tried to use a feature that has been disabled at compilation time.

FILES

      $HOME/.darrc  and  /etc/darrc  if  present  are read for configuration option. They share the same syntax as file
      given to -B option. If $HOME/.darrc is not present and only in that case, /etc/darrc is consulted. You can  still
      launch  /etc/darrc from .darrc using a statement like -B /etc/darrc.  None of theses file need to be present, but
      if they are they are parsed AFTER any option on the command line and AFTER included files from the  command  line
      (files given to the -B option). NOTE: if $HOME is not defined $HOME/.darrc default to /.darrc (at the root of the
      filesystem).
 
      Else you can see conditional syntax bellow, and -N option above that leads  dar  to  ignore  the  /etc/darrc  and
      $HOME/.darrc files.

CONDITIONAL SYNTAX

      configuration  files (-B option, $HOME/.darrc and /etc/darrc) usually contain a simple list of command-line argu-
      ments, split or not over several lines, and eventually mixed with comments (see -B option for more). But, you can
      also use make-like targets to ask for a particular set of commands to be used in certain conditions.
 
      A  condition  takes  the  form of reserved word immediately followed by a colon ':'. This word + colon must stand
      alone on its line, eventually with spaces or tabs beside it. The available conditions are:
 
      extract:            all option listed after this condition get used if previously on command line or file the  -x
                          option has been used
 
      create:             all  option  listed  after  this condition get used if previously on command line or file (-B
                          option) the -c option has been used
 
      listing: (or list:) if -l option has been used
 
      test:               if -t option has been used
 
      diff:               if -d option has been used
 
      isolate:            if -C option has been used
 
      all:                in any case
 
      default:            if no -c, -d, -x, -t, -C or -l has been used at this point of the parsing.
 
      The condition stops when the next condition starts, or at End of File. The commands inserted before any condition
      are equivalent to those inserted after the "all:" condition. Remark : -c -d -x -t -C and -l are mutual exclusive,
      only one of them can be used while calling dar.
 
      Here is an example of conditional syntax
 
             create:
               # upon creation exclude the
               # following files from compression
             -Z "*.mp3" -Z "*.mpg"
 
             all:
             -b
             -p
 
             default:
             # this will get read if not
             # command has been set yet
             -V
             # thus by default dar shows its version
 
             all:
             -v
             # for any command we also ask to be verbose
             # this is added to the previous all: condition
 
      Last point, you may have several time the same condition (several all: ) for example. They will  be  concatenated
      together.

KNOWN BUGS

      dar  cannot restore time of symbolic links. Many (all ?) UNIX do not provide any way to do that, the utime() sys-
      tem call changes the file pointed to by the link rather than the date of the link itself.
 
      dar saves and restores atime and mtime, but cannot restore ctime (last inode change), there does not seems to  be
      a standard call to do that under UNIX.

1:dar

From Linux Man Pages

Contents

SYNOPSIS

DESCRIPTION

OPTIONS

EXPLICIT OPTIONAL ARGUMENTS

EXIT CODES

FILES

CONDITIONAL SYNTAX

RELATED

KNOWN BUGS

CATEGORY

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