How to retrieve the hash for the current commit in

Question

I would like to retain (for now) the ability to link Git changesets to workitems stored in TFS.

I already wrote a tool (using a hook from Git) in which I can inject workitemidentifiers into the message of a Git changeset.

However, I would also like to store the identifier of the Git commit (the hash) into a custom TFS workitem field. This way I can examine a workitem in TFS and see what Git changesets are associated with the workitem.

How can I easily retrieve the hash from the current commit from Git?

Answer 1

Another one, using git log:

git log -1 --format="%H"

It's very similar to the of @outofculture though a bit shorter.

Answer 2

Use git rev-list --max-count=1 HEAD

Answer 3

Here is one-liner in Bash shell using direct read from git files:

(head=($(<.git/HEAD)); cat .git/${head[1]})

^{You need to run above command in your git root folder.}

This method can be useful when you've repository files, but git command has been not installed.

If won't work, check in .git/refs/heads folder what kind of heads do you have present.

Answer 4

If you need to store the hash in a variable during a script, you can use

last_commit=$(git rev-parse HEAD)

Or, if you only want the first 10 characters (like github.com does)

last_commit=$(git rev-parse HEAD | cut -c1-10) 

Answer 5

git show-ref --head --hash head

If you're going for speed though, the approach mentioned by Deestan

cat .git/refs/heads/<branch-name>

is significantly faster than any other method listed here so far.

Answer 6

To turn arbitrary extended object reference into SHA-1, use simply git-rev-parse, for example

git rev-parse HEAD

or

git rev-parse --verify HEAD

Sidenote: If you want to turn references (branches and tags) into SHA-1, there is git show-ref and git for-each-ref.