What is the tree hash of a specific commit hash?

Question

I need a shell command-line which puts the tree hash corresponding to a specific commit hash. I know that git cat-file commit $COMMITID | grep ^tree can do it, but I have to filter the output of that. Is there any command which prints only the hash?

Answer 1

git rev-parse $COMMITID^{tree}

Answer 2

git log -1 --pretty="%T" $COMMITID 

Answer 3

You could rev-parse top-level directory for a commit with a traling colon :

git rev-parse ${COMMITID}: