git-annex-preferred-content(1)

NAME
git-annex-preferred-content - which files are wanted in a repository

DESCRIPTION
Each repository has a preferred content setting, which specifies content that the repository wants to have present. These settings can be configured using git annex vicfg or git annex wanted. They are used by the --auto option, by git annex sync --content, and by the git-annex assistant.

While preferred content expresses a preference, it can be overridden by simply using git annex drop. On the other hand, required content settings are enforced; git annex drop will refuse to drop a file if doing so would violate its required content settings. A repository's required content can be configured using git annex vicfg or git annex required.

SYNTAX
Preferred content expressions use a similar syntax to the git-annex-matching-options(1), without the dashes. For example:

 exclude=archive/* and (include=*.mp3 or smallerthan=1mb)

The idea is that you write an expression that files are matched against. If a file matches, the repository wants to store its content. If it doesn't, the repository wants to drop its content (if there are enough copies elsewhere to allow removing it).

EXPRESSIONS

include=glob / exclude=glob

    Match files to include, or exclude.

    While the command-line options --include=glob and --exclude=glob match files relative to the current directory, preferred content expressions match files relative to the top of the git repository.

    A glob is something like foo.* or b?r. Globs can also contain character classes, like foo[Bb]ar, as well as additional POSIX character classes like [[:space:]]. Which is useful, since a glob in a preferred content expression cannot contain spaces. See the glob(7) man page for more about globs.

    For example, suppose you put files into archive directories when you're done with them. Then you could configure your laptop to prefer to not retain those files, like this: exclude=*/archive/*

    When a subdirectory is being exported or imported to a special remote (see git-annex-export(1)) and git-annex-import(1), these match relative to the top of the subdirectory.

    Note that, when a command is run with the --all option, or in a bare repository, there is no filename associated with an annexed object, and so "include=" and "exclude=" will not match.

copies=number
    Matches only files that git-annex believes to have the specified number of copies, or more. Note that it does not check remotes to verify that the copies still exist.

    To decide if content should be dropped, git-annex evaluates the preferred content expression under the assumption that the content has *already* been dropped. If the content would not be wanted then, the drop can be done. So, for example, copies=2 in a preferred content expression lets content be dropped only when there are currently 3 copies of it, including the repo it's being dropped from. This is different than running git annex drop --copies=2, which will drop files that currently have 2 copies.

copies=trustlevel:number
    Matches only files that git-annex believes have the specified number copies, on remotes with the specified trust level. For example, copies=trusted:2

    To match any trust level at or higher than a given level, use trustlevel+. For example, copies=semitrusted+:2

copies=groupname:number
    Matches only files that git-annex believes have the specified number of copies, on remotes in the specified group. For example, copies=archive:2

    Preferred content expressions have no equivalent to the --in option, but groups can accomplish similar things. You can add repositories to groups, and match against the groups in a preferred content expression. So rather than --in=usbdrive, put all the USB drives into a "transfer" group, and use copies=transfer:1

lackingcopies=number
    Matches only files that git-annex believes need the specified number or more additional copies to be made in order to satisfy their numcopies settings.

approxlackingcopies=number
    Like lackingcopies, but does not look at .gitattributes annex.numcopies settings. This makes it significantly faster.

inbackend=backendname
    Matches only files whose content is stored using the specified key-value backend.

    See git-annex-backends(1) for information about available backends.

securehash
    Matches only files whose content is hashed using a cryptographically secure function.

inallgroup=groupname
    Matches only files that git-annex believes are present in all repositories in the specified group.

onlyingroup=groupname
    Matches files that git-annex believes are present in at least one repository that is in the specified group, and are not present in any repositories that are not in the specified group.

smallerthan=size / largerthan=size
    Matches only files whose content is smaller than, or larger than the specified size.

    The size can be specified with any commonly used units, for example, "0.5 gb" or "100 KiloBytes"

metadata=field=glob
    Matches only files that have a metadata field attached with a value that matches the glob. The values of metadata fields are matched case insensitively.

    A glob is something like foo.* or b?r. Globs can also contain character classes, like foo[Bb]ar, as well as additional POSIX character classes like [[:space:]]. Which is useful, since a glob in a preferred content expression cannot contain spaces. See the glob(7) man page for more about globs.

    To match a tag "done", use metadata=tag=done

    To match author metadata, use metadata=author=*Smith

metadata=field<number / metadata=field>number

metadata=field<=number / metadata=field>=number
    Matches only files that have a metadata field attached with a value that is a number and is less than or greater than the specified number.

    To match PDFs with between 100 and 200 pages (assuming something has set that metadata), use metadata=pagecount>=100 and metadata=pagecount<=200

present
    Makes content be wanted if it's present, but not otherwise.

    This leaves it up to you to use git-annex manually to move content around. You can use this to avoid preferred content settings from affecting a subdirectory. For example: auto/* or (include=ad-hoc/* and present)

    Note that not present is a very bad thing to put in a preferred content expression. It'll make it want to get content that's not present, and drop content that is present! Don't go there..

inpreferreddir
    Makes content be preferred if it's in a directory (located anywhere in the tree) with a particular name.

    The name of the directory can be configured using git annex enableremote $remote preferreddir=$dirname

    (If no directory name is configured, it uses "public" by default.)

    Note that, when a command is run with the --all option, or in a bare repository, there is no filename associated with an annexed object, and so "inpreferreddir" will not match.

standard
    git-annex comes with some built-in preferred content expressions, that can be used with repositories that are in some standard groups such as "client" and "transfer".

    When a repository is in exactly one such group, you can use the "standard" keyword in its preferred content expression, to match whatever content the group's expression matches.

    Most often, the whole preferred content expression is simply "standard". But, you can do more complicated things, for example: standard or include=otherdir/*

groupwanted
    The "groupwanted" keyword can be used to refer to a preferred content expression that is associated with a group, as long as there is exactly one such expression amoung the groups a repository is in. This is like the "standard" keyword, but you can configure the preferred content expressions using git annex groupwanted.

    When writing a groupwanted preferred content expression, you can use all the keywords documented here, including "standard". (But not "groupwanted".)

    For example, to make a variant of the standard client preferred content expression that does not want files in the "out" directory, you could run: git annex groupwanted client "standard and exclude=out/*"

    Then repositories that are in the client group and have their preferred content expression set to "groupwanted" will use that, while other client repositories that have their preferred content expression set to "standard" will use the standard expression.

    Or, you could make a new group, with your own custom preferred content expression tuned for your needs, and every repository you put in this group and make its preferred content be "groupwanted" will use it.

    For example, the archive group only wants to archive 1 copy of each file, spread among every repository in the group. Here's how to configure a group named redundantarchive, that instead wants to contain 3 copies of each file:

     git annex groupwanted redundantarchive "not (copies=redundantarchive:3)"
     for repo in foo bar baz; do
         git annex group $repo redundantarchive
         git annex wanted $repo groupwanted
     done

unused
    Matches only keys that git annex unused has determined to be unused.

    This is related the the --unused option. However, putting unused in a preferred content expression doesn't make git-annex consider those unused keys. So when git-annex is only checking preferred content expressions against files in the repository (which are obviously used), unused in a preferred content expression won't match anything.

    So when is unused useful in a preferred content expression?

    Using git annex sync --content --all will operate on all files, including unused ones, and take unused in preferred content expressions into account.

    The git-annex assistant periodically scans for unused files, and moves them to some repository whose preferred content expression says it wants them. (Or, if annex.expireunused is set, it may just delete them.)

anything
    Always matches.

nothing
    Never matches. (Same as "not anything")

not expression
    Inverts what the expression matches. For example, not include=archive/* is the same as exclude=archive/*

and / or / ( expression )
    These can be used to build up more complicated expressions.

TESTING
To check at the command line which files are matched by a repository's preferred content settings, you can use the --want-get and --want-drop options.

For example, git annex find --want-get --not --in . will find all the files that git annex get --auto will want to get, and git annex find --want-drop --in . will find all the files that git annex drop --auto will want to drop.

The --explain option can be used to understand why a complex preferred content expression matches or fails to match. The expression will be displayed, with each term followed by "[TRUE]" or "[FALSE]" to indicate the value. Irrelevant terms will be ommitted from the explanation, for example "exclude=* and copies=1" will be displayed as "exclude=*[FALSE]"

SEE ALSO
git-annex(1)

git-annex-vicfg(1)

git-annex-wanted(1)

<https://git-annex.branchable.com/preferred_content/>

<https://git-annex.branchable.com/preferred_content/standard_groups/>

AUTHOR
Joey Hess <id@joeyh.name>

<http://git-annex.branchable.com/>