borg export-tar

borg [common options] export-tar [options] NAME FILE [PATH...]

positional arguments
	NAME	specify the archive name
	FILE	output tar file. “-” to write to stdout instead.
	PATH	paths to extract; patterns are supported
optional arguments
	--tar-filter	filter program to pipe data through
	--list	output verbose list of items (files, dirs, …)
	--tar-format FMT	select tar format: BORG, PAX or GNU
Common options
Exclusion options
	-e PATTERN, --exclude PATTERN	exclude paths matching PATTERN
	--exclude-from EXCLUDEFILE	read exclude patterns from EXCLUDEFILE, one per line
	--pattern PATTERN	include/exclude paths matching PATTERN
	--patterns-from PATTERNFILE	read include/exclude patterns from PATTERNFILE, one per line
	--strip-components NUMBER	Remove the specified number of leading path elements. Paths with fewer elements will be silently skipped.

Description

This command creates a tarball from an archive.

When giving ‘-’ as the output FILE, Borg will write a tar stream to standard output.

By default (--tar-filter=auto) Borg will detect whether the FILE should be compressed based on its file extension and pipe the tarball through an appropriate filter before writing it to FILE:

• .tar.gz or .tgz: gzip
• .tar.bz2 or .tbz: bzip2
• .tar.xz or .txz: xz
• .tar.zstd: zstd
• .tar.lz4: lz4

Alternatively, a --tar-filter program may be explicitly specified. It should read the uncompressed tar stream from stdin and write a compressed/filtered tar stream to stdout.

Depending on the -tar-format option, these formats are created:

--tar-format	Specification	Metadata
BORG	BORG specific, like PAX	all as supported by borg
PAX	POSIX.1-2001 (pax) format	GNU + atime/ctime/mtime ns
GNU	GNU tar format	mtime s, no atime/ctime, no ACLs/xattrs/bsdflags

A --sparse option (as found in borg extract) is not supported.

By default the entire archive is extracted but a subset of files and directories can be selected by passing a list of PATHs as arguments. The file selection can further be restricted by using the --exclude option.

For more help on include/exclude patterns, see the borg help patterns command output.

--progress can be slower than no progress display, since it makes one additional pass over the archive metadata.

borg import-tar

borg [common options] import-tar [options] NAME TARFILE

positional arguments
	NAME	specify the archive name
	TARFILE	input tar file. “-” to read from stdin instead.
optional arguments
	--tar-filter	filter program to pipe data through
	-s, --stats	print statistics for the created archive
	--list	output verbose list of items (files, dirs, …)
	--filter STATUSCHARS	only display items with the given status characters
	--json	output stats as JSON (implies --stats)
Common options
Archive options
	--comment COMMENT	add a comment text to the archive
	--timestamp TIMESTAMP	manually specify the archive creation date/time (UTC, yyyy-mm-ddThh:mm:ss format). alternatively, give a reference file/directory.
	-c SECONDS, --checkpoint-interval SECONDS	write checkpoint every SECONDS seconds (Default: 1800)
	--chunker-params PARAMS	specify the chunker parameters (ALGO, CHUNK_MIN_EXP, CHUNK_MAX_EXP, HASH_MASK_BITS, HASH_WINDOW_SIZE). default: buzhash,19,23,21,4095
	-C COMPRESSION, --compression COMPRESSION	select compression algorithm, see the output of the “borg help compression” command for details.

Description

This command creates a backup archive from a tarball.

When giving ‘-’ as path, Borg will read a tar stream from standard input.

By default (--tar-filter=auto) Borg will detect whether the file is compressed based on its file extension and pipe the file through an appropriate filter:

• .tar.gz or .tgz: gzip -d
• .tar.bz2 or .tbz: bzip2 -d
• .tar.xz or .txz: xz -d
• .tar.zstd: zstd -d
• .tar.lz4: lz4 -d

Alternatively, a --tar-filter program may be explicitly specified. It should read compressed data from stdin and output an uncompressed tar stream on stdout.

Most documentation of borg create applies. Note that this command does not support excluding files.

A --sparse option (as found in borg create) is not supported.

About tar formats and metadata conservation or loss, please see borg export-tar.

import-tar reads these tar formats:

• BORG: borg specific (PAX-based)
• PAX: POSIX.1-2001
• GNU: GNU tar
• POSIX.1-1988 (ustar)
• UNIX V7 tar
• SunOS tar with extended attributes

Examples

# export as uncompressed tar
$ borg export-tar Monday Monday.tar

# import an uncompressed tar
$ borg import-tar Monday Monday.tar

# exclude some file types, compress using gzip
$ borg export-tar Monday Monday.tar.gz --exclude '*.so'

# use higher compression level with gzip
$ borg export-tar --tar-filter="gzip -9" Monday Monday.tar.gz

# copy an archive from repoA to repoB
$ borg -r repoA export-tar --tar-format=BORG archive - | borg -r repoB import-tar archive -

# export a tar, but instead of storing it on disk, upload it to remote site using curl
$ borg export-tar Monday - | curl --data-binary @- https://somewhere/to/POST

# remote extraction via "tarpipe"
$ borg export-tar Monday - | ssh somewhere "cd extracted; tar x"

Archives transfer script

Outputs a script that copies all archives from repo1 to repo2:

for A T in `borg list --format='{archive} {time:%Y-%m-%dT%H:%M:%S}{LF}'`
do
  echo "borg -r repo1 export-tar --tar-format=BORG $A - | borg -r repo2 import-tar --timestamp=$T $A -"
done

Kept:

• archive name, archive timestamp
• archive contents (all items with metadata and data)

Lost:

• some archive metadata (like the original commandline, execution time, etc.)

Please note:

• all data goes over that pipe, again and again for every archive
• the pipe is dumb, there is no data or transfer time reduction there due to deduplication
• maybe add compression
• pipe over ssh for remote transfer
• no special sparse file support