What's the best way to extract a tree from a git repository?

Question

Extracting a blob (file) from an arbitrary revision is easy with git show, e.g.:

 git show master:src/hello-world.c > /tmp/hello.c

However, I'd like to know if is there a similar way in git to extract a tree (directory) and everything under it recursively?

I've written a small script that does this, so I'll add that as a possible answer. It seems that this is the kind of thing that may well be built in to git, but I just don't know how to find it...

Answer 1

You can use git archive for this.

git archive master:src/ | tar -C destination -x

Answer 2

You can use read-tree and checkout-index with a temporary index file:

GIT_INDEX_FILE=.tmp.index { git read-tree master:src &&
                            git checkout-index -a --prefix=dest/; 
                            rm -f .tmp.index; }

(Line breaks added for clarity, but it's really a one-liner.)

For a bare repository you have to pretend that a working tree exists and that you are in it:

GIT_INDEX_FILE=.tmp.index GIT_DIR=/path/to/repo.git GIT_WORK_TREE=. {
    git read-tree master:src &&
    git checkout-index -a --prefix=/path/to/dest/; 
    rm -f .tmp.index; }

If run from inside the bare repository you can omit setting GIT_DIR.

Answer 3

I'm doing this at the moment with this script:

http://gist.github.com/498447

... which parses the output of git ls-tree -r -z <tree-ish>. You can pass it anything that git ls-tree can understand as a tree, e.g:

extract-tree-from-git.py master:src/tests/ /tmp/extracted-tests/
extract-tree-from-git.py HEAD^ /tmp/parent-of-head/