Unstage

To remove files from stage use reset HEAD where HEAD is the last commit of the current branch. This will unstage the file but maintain the modifications.
```
git reset HEAD <file>
```
To revert the file back to the state it was in before the changes we can use:
```
git checkout -- <file>
```
To remove a file from disk and repo use 'git rm' and to rm a dir use the '-r' flag:
```
git rm '*.txt'
git rm -r <dirname>
```
If we want to remove a file from the repository but keep it on disk, say we forgot to add it to our .gitignore file then use --cache:
```
git rm <filename> --cache
```