47 lines
2.2 KiB
Markdown
47 lines
2.2 KiB
Markdown
git-annex allows you to store arbitrary metadata about files stored in the
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git-annex repository. The metadata is stored in the `git-annex` branch, and
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so is automatically kept in sync with the rest of git-annex's state, such
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as [[location_tracking]] information.
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Some of the things you can do with metadata include:
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* Using `git annex metadata file` to show all
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the metadata associated with a file.
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* [[tips/metadata_driven_views]]
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* Limiting the files git-annex commands act on to those with
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or without particular metadata.
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For example `git annex find --metadata tag=foo --or --metadata tag=bar`
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* Using it in [[preferred_content]] expressions.
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For example "tag=important or not author=me"
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Each file (actually the underlying key) can have any number of metadata
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fields, which each can have any number of values. For example, to tag
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files, the `tag` field is typically used, with values set to each tag that
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applies to the file.
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The field names are limited to alphanumerics (and `[_-.]`), and are case
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insensitive. The metadata values can contain absolutely anything you
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like -- but you're recommended to keep it simple and reasonably short.
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Here are some metadata fields that git-annex has special support for:
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* `tag` - With each tag being a different value.
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* `year`, `month` - When this particular version of the file came into
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being.
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* `$field-lastchanged` - This is automatically maintained for each
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field that's set, and gives the date and time of the most recent
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change to the field. It cannot be modified directly.
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* `lastchanged` - This is automatically maintained, giving the data and time
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of the last change to any of the metadata of a file.
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To make git-annex automatically set the year and month when adding files,
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run `git config annex.genmetadata true`. Also, see
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[[tips/automatically_adding_metadata]].
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git-annex's metadata can be updated in a distributed fashion. For example,
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two users, each with their own clone of a repository, can set and unset
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metadata at the same time, even for the same field of the same file.
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When they push their changes, `git annex merge` will combine their
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metadata changes in a consistent and (probably) intuitive way.
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See [[the metadata design page|design/metadata]] for more details.
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