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.

       So,  when  you  give  relative/  as  root, the paths going into the matcher will look like
       relative/.../file.ext.  When  you  give  /absolute/  as  root,   they   will   look   like
       /absolute/.../file.ext. This is meant when we talk about "full path" below.

       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.
       Therefore, always use relative paths in your patterns when  matching  archive  content  in
       commands  like  extract or mount. Starting with Borg 1.2 this behaviour will be changed to
       accept both absolute and relative paths.

       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 experimental --pattern option.

       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.

       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.

       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.

       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.

              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
       experimental  --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  --exlude-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  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
          # don't backup the other home directories
          - /home/*
          # don't even look in /proc
          ! /proc

AUTHOR

       The Borg Collective

                                            2020-12-24                           BORG-PATTERNS(1)