[[!comment format=mdwn
 username="chkno@50332f55d5ef2f4b7c6bec5253b853a8f2dc770e"
 nickname="chkno"
 avatar="http://cdn.libravatar.org/avatar/8194377c81da838dda761a5d93b9c25c"
 subject="Interim shell script"
 date="2020-02-04T07:26:10Z"
 content="""
Until this feature is available in git annex proper, here is a small shell script that uses [lndir](https://gitlab.freedesktop.org/xorg/util/lndir) to create a merged view of the .git/annex/objects areas of multiple git-annex repositories.

* [union-link-annexes](https://chkno.net/union-link-annexes)

Demo:

    $ git init repo1
    $ cd repo1
    $ git annex init repo1
    $ echo from1 > from1
    $ echo both > both
    $ git annex add from1 both
    $ git commit -m .

    $ cd ..
    $ git clone repo1 repo2
    $ cd repo2
    $ echo from2 > from2
    $ git annex add from2
    $ git annex copy --from origin both
    $ git annex sync
    $ git annex list
    here
    |origin
    ||
    XX both
    _X from1
    X_ from2

    $ cd ../repo1
    $ git annex sync
    $ cd ..


    $ union-link-annexes merged repo1 repo2


    $ grep . repo1/*
    repo1/both:both
    repo1/from1:from1
    grep: repo1/from2: No such file or directory

    $ grep . repo2/*
    repo2/both:both
    grep: repo2/from1: No such file or directory
    repo2/from2:from2

    $ grep . merged/*
    merged/both:both
    merged/from1:from1
    merged/from2:from2

    $ find merged -not -type d -printf '%p -> %l\n'
    merged/both -> .git/annex/objects/XV/zk/SHA256E-s5--f6d...
    merged/from1 -> .git/annex/objects/vf/8W/SHA256E-s6--16e...
    merged/from2 -> .git/annex/objects/3M/P2/SHA256E-s6--21e...
    merged/.git/annex/objects/vf/8W/SHA256E-s6--16e... -> ../../../../../../../repo1/.git/annex/objects/vf/8W/SHA256E-s6--16e...
    merged/.git/annex/objects/XV/zk/SHA256E-s5--f6d... -> ../../../../../../../repo1/.git/annex/objects/XV/zk/SHA256E-s5--f6d...
    merged/.git/annex/objects/3M/P2/SHA256E-s6--21e... -> ../../../../../../../repo2/.git/annex/objects/3M/P2/SHA256E-s6--21e...
"""]]