git-annex/doc/tips/automatically_adding_metadata.mdwn

git-annex's [[metadata]] works best when files have a lot of useful
metadata attached to them.

To make git-annex automatically set the year and month when adding files,
run `git config annex.genmetadata true`.

A git commit hook can be set up to extract lots of metadata from files
like photos, mp3s, etc.

* Install the `extract` utility, from <http://www.gnu.org/software/libextractor/>  
  `apt-get install extract`
* Download [[pre-commit-annex]] and install it in your git-annex repository
  as `.git/hooks/pre-commit-annex`.  
  Remember to make the script executable!
* Run: `git config metadata.extract "artist album title camera_make video_dimensions"`

Now any fields you list in metadata.extract to will be extracted and
stored when files are committed.

To get a list of all possible fields, run: `extract -L | sed ' ' _`

By default, if a git-annex already has a metadata field for a file,
its value will not be overwritten with metadata taken from files.
To allow overwriting, run: `git config metadata.overwrite true`
pre-commit-annex hook script to automatically extract metadata from lots of types of files Using the extract(1) program to do the heavy lifting. Decided to make git-annex run pre-commit-annex when committing. Since git-annex pre-commit also runs it, it'll be run when git commit is run too, via the pre-commit hook. This basically gives back the pre-commit hook that git-annex took away. The implementation avoids repeatedly looking for the hook script when the assistant is running and committing repeatedly; only checks if the hook is available once. To make the script simpler, made git-annex metadata -s field?=value only set a field when it's not already got a value. This commit was sponsored by bak. 2014-03-02 22:01:07 +00:00			`git-annex's [[metadata]] works best when files have a lot of useful`
			`metadata attached to them.`

			`To make git-annex automatically set the year and month when adding files,`
			run `git config annex.genmetadata true`.

			`A git commit hook can be set up to extract lots of metadata from files`
			`like photos, mp3s, etc.`

			* Install the `extract` utility, from <http://www.gnu.org/software/libextractor/>
			`apt-get install extract`
			`* Download [[pre-commit-annex]] and install it in your git-annex repository`
			as `.git/hooks/pre-commit-annex`.
			`Remember to make the script executable!`
			* Run: `git config metadata.extract "artist album title camera_make video_dimensions"`

			`Now any fields you list in metadata.extract to will be extracted and`
			`stored when files are committed.`

			To get a list of all possible fields, run: `extract -L \| sed ' ' _`

			`By default, if a git-annex already has a metadata field for a file,`
			`its value will not be overwritten with metadata taken from files.`
			To allow overwriting, run: `git config metadata.overwrite true`