# git

## Reverting a single file to a specific commit

First, we'll need to find the hash of the commit that we want to revert to. This can be done via

```bash
> git log -p filename
```

When we know the hash, we checkout the desired file to the desired hash:

```bash
> git checkout [hash] -- path/to/file
```

## Useful commands

### Remove local branches that have been deleted in the remote repository

`git fetch --prune` removes any remote-tracking references that no longer exist on the remote before fetching.

### Temporarily ignoring files

There are cases where you want to temporarily ignore files, but do not want them to be untracked in general (i.e. if you and your team aggreed to not check in `schema.rb` files in Pull Requests in a rails project). To acheive that, just run

```
git update-index --assume-unchanged <file>
```

If you later want to track this file again (i.e. when you are checking out master), run

```
git update-index --no-assume-unchanged <file>
```

### Undo the last commit but keep the changes

Sometimes, I do commit changes I did, but only want to do so temporarily. This is the case, for example, when wanting to change a branch, but having changes in the current branch, where `git stash` is not an option (e.g. because there are untracked files present).\
To undo this commit, simply use

```
git reset HEAD^
```

### Check in changes in filename casing

When changing the casing of a file, git does (under certain circumstances) not recognize the changes. To get the changes checked in, there is a simple workaround.\
Assuming the file `Myfile.txt` was changed to `myfile.txt`, you can

1. Rename the file to something entirely new (`mv myfile.txt myfile_tmp.txt`) &#x20;
2. Check that new file in (`git add myfile_tmp.txt`) &#x20;
3. Name the file back to the originally inteded name (`mv myfile_tmp.txt myfile.txt`) &#x20;
4. Check the file in again (`git add myfile.txt`) &#x20;

Git should now recognize the changed casing in the filename.