path: root/_tils/2020-08-14-browse-a-git-repository-at-a-specific-commit.md

---
title: Browse a git repository at a specific commit
date: 2020-08-14
layout: til
lang: en
ref: browse-a-git-repository-at-a-specific-commit
---

I commonly use tools like `git log` together with `git show` when inspecting
past changes in a repository:

```shell
git log
# search for a the commit I'm looking for
git show <my-commit>
# see the diff for the commit
```

But I also wanted to not only be able to look at the diff of a specific commit,
but to browse the whole repository at that specific commit.

I used to accomplish it the "brute force" way: clone the whole repository in
another folder and checkout the commit there:

```shell
git clone <original-repo> /tmp/tmp-repo-clone
cd /tmp-repo-clone
git checkout <my-commit>
```

But git itself allows we to specific the directory of the checkout by using the
`--work-tree` global git flag. This is what `man git` says about it:

```txt
--work-tree=<path>
    Set the path to the working tree. It can be an absolute path or a path relative to the current working
    directory. This can also be controlled by setting the GIT_WORK_TREE environment variable and the
    core.worktree configuration variable (see core.worktree in git-config(1) for a more detailed
    discussion).
```

So it allows us to set the desired path of the working tree. So if we want to
copy the contents of the current working tree into `copy/`:

```shell
mkdir copy
git --work-tree=copy/ checkout .
```

After that `copy/` will contain a replica of the code in HEAD. But to checkout a
specific, we need some extra parameters:

```shell
git --work-tree=<dir> checkout <my-commit> -- .
```

There's an extra `-- .` at the end, which initially looks like we're sending
Morse signals to git, but we're actually saying to `git-checkout` which
sub directory of `<my-commit>` we want to look at. Which means we can do
something like:

```shell
git --work-tree=<dir> checkout <my-commit> -- src/
```

And with that `<dir>` will only contain what was inside `src/` at `<commit>`.

After any of those checkouts, you have to `git reset .` to reset your current
staging area back to what it was before the checkout.


## References:

1. [GIT: Checkout to a specific folder][0] (StackOverflow)

[0]: https://stackoverflow.com/a/16493707