Provided by: borgbackup_1.2.2-1_amd64 
NAME
borg-patterns - Details regarding patterns
DESCRIPTION
The path/filenames used as input for the pattern matching start from the currently active
recursion root. You usually give the recursion root(s) when invoking borg and these can be
either relative or absolute paths.
If you give /absolute/ as root, the paths going into the matcher will look relative like
absolute/.../file.ext, because file paths in Borg archives are always stored normalized
and relative. This means that e.g. borg create /path/to/repo ../some/path will store all
files as some/path/.../file.ext and borg create /path/to/repo /home/user will store all
files as home/user/.../file.ext.
A directory exclusion pattern can end either with or without a slash ('/'). If it ends
with a slash, such as some/path/, the directory will be included but not its content. If
it does not end with a slash, such as some/path, both the directory and content will be
excluded.
File patterns support these styles: fnmatch, shell, regular expressions, path prefixes and
path full-matches. By default, fnmatch is used for --exclude patterns and shell-style is
used for the --pattern option. For commands that support patterns in their PATH argument
like (borg list), the default pattern is path prefix.
Starting with Borg 1.2, discovered fs paths are normalised, have leading slashes removed
and then are matched against your patterns. Note: You need to review your include /
exclude patterns and make sure they do not expect leading slashes. Borg can only deal with
this for some very simple patterns by removing leading slashes there also.
If followed by a colon (':') the first two characters of a pattern are used as a style
selector. Explicit style selection is necessary when a non-default style is desired or
when the desired pattern starts with two alphanumeric characters followed by a colon (i.e.
aa:something/*).
Fnmatch, selector fm:
This is the default style for --exclude and --exclude-from. These patterns use a
variant of shell pattern syntax, with '*' matching any number of characters, '?'
matching any single character, '[...]' matching any single character specified,
including ranges, and '[!...]' matching any character not specified. For the
purpose of these patterns, the path separator (backslash for Windows and '/' on
other systems) is not treated specially. Wrap meta-characters in brackets for a
literal match (i.e. [?] to match the literal character ?). For a path to match a
pattern, the full path must match, or it must match from the start of the full path
to just before a path separator. Except for the root path, paths will never end in
the path separator when matching is attempted. Thus, if a given pattern ends in a
path separator, a '*' is appended before matching is attempted. A leading path
separator is always removed.
Shell-style patterns, selector sh:
This is the default style for --pattern and --patterns-from. Like fnmatch patterns
these are similar to shell patterns. The difference is that the pattern may include
**/ for matching zero or more directory levels, * for matching zero or more
arbitrary characters with the exception of any path separator. A leading path
separator is always removed.
Regular expressions, selector re:
Regular expressions similar to those found in Perl are supported. Unlike shell
patterns regular expressions are not required to match the full path and any
substring match is sufficient. It is strongly recommended to anchor patterns to the
start ('^'), to the end ('$') or both. Path separators (backslash for Windows and
'/' on other systems) in paths are always normalized to a forward slash ('/')
before applying a pattern. The regular expression syntax is described in the Python
documentation for the re module.
Path prefix, selector pp:
This pattern style is useful to match whole sub-directories. The pattern
pp:root/somedir matches root/somedir and everything therein. A leading path
separator is always removed.
Path full-match, selector pf:
This pattern style is (only) useful to match full paths. This is kind of a pseudo
pattern as it can not have any variable or unspecified parts - the full path must
be given. pf:root/file.ext matches root/file.ext only. A leading path separator is
always removed.
Implementation note: this is implemented via very time-efficient O(1) hashtable
lookups (this means you can have huge amounts of such patterns without impacting
performance much). Due to that, this kind of pattern does not respect any context
or order. If you use such a pattern to include a file, it will always be included
(if the directory recursion encounters it). Other include/exclude patterns that
would normally match will be ignored. Same logic applies for exclude.
NOTE:
re:, sh: and fm: patterns are all implemented on top of the Python SRE engine. It is
very easy to formulate patterns for each of these types which requires an inordinate
amount of time to match paths. If untrusted users are able to supply patterns, ensure
they cannot supply re: patterns. Further, ensure that sh: and fm: patterns only
contain a handful of wildcards at most.
Exclusions can be passed via the command line option --exclude. When used from within a
shell, the patterns should be quoted to protect them from expansion.
The --exclude-from option permits loading exclusion patterns from a text file with one
pattern per line. Lines empty or starting with the number sign ('#') after removing
whitespace on both ends are ignored. The optional style selector prefix is also supported
for patterns loaded from a file. Due to whitespace removal, paths with whitespace at the
beginning or end can only be excluded using regular expressions.
To test your exclusion patterns without performing an actual backup you can run borg
create --list --dry-run ....
Examples:
# Exclude '/home/user/file.o' but not '/home/user/file.odt':
$ borg create -e '*.o' backup /
# Exclude '/home/user/junk' and '/home/user/subdir/junk' but
# not '/home/user/importantjunk' or '/etc/junk':
$ borg create -e 'home/*/junk' backup /
# Exclude the contents of '/home/user/cache' but not the directory itself:
$ borg create -e home/user/cache/ backup /
# The file '/home/user/cache/important' is *not* backed up:
$ borg create -e home/user/cache/ backup / /home/user/cache/important
# The contents of directories in '/home' are not backed up when their name
# ends in '.tmp'
$ borg create --exclude 're:^home/[^/]+\.tmp/' backup /
# Load exclusions from file
$ cat >exclude.txt <<EOF
# Comment line
home/*/junk
*.tmp
fm:aa:something/*
re:^home/[^/]+\.tmp/
sh:home/*/.thumbnails
# Example with spaces, no need to escape as it is processed by borg
some file with spaces.txt
EOF
$ borg create --exclude-from exclude.txt backup /
A more general and easier to use way to define filename matching patterns exists with the
--pattern and --patterns-from options. Using these, you may specify the backup roots
(starting points) and patterns for inclusion/exclusion. A root path starts with the
prefix R, followed by a path (a plain path, not a file pattern). An include rule starts
with the prefix +, an exclude rule starts with the prefix -, an exclude-norecurse rule
starts with !, all followed by a pattern.
NOTE:
Via --pattern or --patterns-from you can define BOTH inclusion and exclusion of files
using pattern prefixes + and -. With --exclude and --exclude-from ONLY excludes are
defined.
Inclusion patterns are useful to include paths that are contained in an excluded path. The
first matching pattern is used so if an include pattern matches before an exclude pattern,
the file is backed up. If an exclude-norecurse pattern matches a directory, it won't
recurse into it and won't discover any potential matches for include rules below that
directory.
NOTE:
It's possible that a sub-directory/file is matched while parent directories are not.
In that case, parent directories are not backed up thus their user, group, permission,
etc. can not be restored.
Note that the default pattern style for --pattern and --patterns-from is shell style
(sh:), so those patterns behave similar to rsync include/exclude patterns. The pattern
style can be set via the P prefix.
Patterns (--pattern) and excludes (--exclude) from the command line are considered first
(in the order of appearance). Then patterns from --patterns-from are added. Exclusion
patterns from --exclude-from files are appended last.
Examples:
# backup pics, but not the ones from 2018, except the good ones:
# note: using = is essential to avoid cmdline argument parsing issues.
borg create --pattern=+pics/2018/good --pattern=-pics/2018 repo::arch pics
# use a file with patterns:
borg create --patterns-from patterns.lst repo::arch
The patterns.lst file could look like that:
# "sh:" pattern style is the default, so the following line is not needed:
P sh
R /
# can be rebuild
- home/*/.cache
# they're downloads for a reason
- home/*/Downloads
# susan is a nice person
# include susans home
+ home/susan
# also back up this exact file
+ pf:home/bobby/specialfile.txt
# don't backup the other home directories
- home/*
# don't even look in /proc
! proc
You can specify recursion roots either on the command line or in a patternfile:
# these two commands do the same thing
borg create --exclude home/bobby/junk repo::arch /home/bobby /home/susan
borg create --patterns-from patternfile.lst repo::arch
The patternfile:
# note that excludes use fm: by default and patternfiles use sh: by default.
# therefore, we need to specify fm: to have the same exact behavior.
P fm
R /home/bobby
R /home/susan
- home/bobby/junk
This allows you to share the same patterns between multiple repositories without needing
to specify them on the command line.
AUTHOR
The Borg Collective
2022-08-20 BORG-PATTERNS(1)