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

To get the full SHA:

$ git rev-parse HEAD
cbf1b9a1be984a9f61b79a05f23b19f66d533537

To get the shortened version:

$ git rev-parse --short HEAD
cbf1b9a

Answer 2

Here is another way of doing it with :)

git log | grep -o '\w\{8,\}' | head -n 1

Answer 3

Perhaps you want an alias so you don't have to remember all the nifty details. After doing one of the below steps, you will be able to simply type:

$ git lastcommit
49c03fc679ab11534e1b4b35687b1225c365c630

Following up on the accepted answer, here are two ways to set this up:

1) Teach git the explicit way by editing the global config (my original answer):

 # open the git config editor
 $ git config --global --edit
 # in the alias section, add
 ...
 [alias]
   lastcommit = rev-parse HEAD
 ...

2) Or if you like a shortcut to teach git a shortcut, as recently commented by Adrien:

$ git config --global alias.lastcommit "rev-parse HEAD"

From here on, use git lastcommit to show the last commit's hash.

Answer 4

in your home-dir in file ".gitconfig" add the following

[alias]
sha = rev-parse HEAD

then you will have an easier command to remember:

$ git sha
59fbfdbadb43ad0b6154c982c997041e9e53b600

Answer 5

I needed something a little more different: display the full sha1 of the commit, but append an asterisk to the end if the working directory is not clean. Unless I wanted to use multiple commands, none of the options in the previous answers work.

Here is the one liner that does:
git describe --always --abbrev=0 --match "NOT A TAG" --dirty="*"
Result: f5366ccb21588c0d7a5f7d9fa1d3f85e9f9d1ffe*

Explanation: describes (using annotated tags) the current commit, but only with tags containing "NOT A TAG". Since tags cannot have spaces, this never matches a tag and since we want to show a result --always, the command falls back displaying the full (--abbrev=0) sha1 of the commit and it appends an asterisk if the working directory is --dirty.

If you don't want to append the asterisk, this works like all the other commands in the previous answers:
git describe --always --abbrev=0 --match "NOT A TAG"
Result: f5366ccb21588c0d7a5f7d9fa1d3f85e9f9d1ffe

Answer 6

If you want the super-hacky way to do it:

cat .git/`cat .git/HEAD | cut -d \  -f 2`

Basically, git stores the location of HEAD in .git/HEAD, in the form ref: {path from .git}. This command reads that out, slices off the "ref: ", and reads out whatever file it pointed to.

This, of course, will fail in detached-head mode, as HEAD won't be "ref:...", but the hash itself - but you know, I don't think you expect that much smarts in your bash one-liners. If you don't think semicolons are cheating, though...

HASH="ref: HEAD"; while [[ $HASH == ref\:* ]]; do HASH="$(cat ".git/$(echo $HASH | cut -d \  -f 2)")"; done; echo $HASH