nix-config/help/git.md

# Git

## Common commands

- Start a new git repository: `git init` **OR** `gi`
- Add files to commit: `git add <files>` **OR** `ga <files>`
- Commit those files to the repository: `git commit -m <message>` **OR** `gc <message>`
- Undo the last commit: `gr`
- Undo the last commit and delete changes: `grr`
- Update your local repository with a remote repository: `git pull -u <remote> <branch>`
    - The most common use is `git pull -u origin master`, although this also works for upstream remotes
- Show the status of the local repository: `git status` **OR** `gs` **OR** `git s`
- Push changes from your local repository to a remote repository: `git push <remote> <branch>` **OR** `git push` **OR** `gp`
    - The most common use is `git push origin master`, which is usually the default for `git push`
- Show the difference between the staging area and the working tree: `git diff` **OR** `gd`
    - Show the changes that you added but haven't committed yet: `git diff --staged` **OR** `gd --staged` **OR** `gds`
- Show a log of all the commits: `git log` (full log) **OR** `git lg` (commits only, easier to read)
- Edit the last commit message: `git commit --amend`
- Commit a file one part at a time: `git add --patch <file_name>` **OR** `ga --patch <file_name>` **OR** `gap <file_name>`
    - Useful when you made a lot of changes to a file and need to commit it
    - Enables you to commit certain parts of a file and not the entire thing
    - Note that if the file is not in the repository yet, you should do `git add -N <file_name>` or `ga -N <file_name>`
    - Go to the next section: `j`
    - Go to the previous section: `k`
    - Stage this section for the next commit: `y`
    - Do not stage this section for the next commit: `n`
    - Quit and do not stage this section or any of the remaining sections: `q`
    - Split the current section into smaller sections: `s`
    - Manually edit the current section: `e`

Note that the `-u` flag means `set-(u)pstream-to`. It records the location so you don't have to set which remote to push or pull from every time.

Also note that `git clone` makes a remote name of `origin` by default. This is why `git push -u origin master` is usually used.

### Working with Branches

- Show all the branches: `git branch -a`
- Checkout a different branch: `git checkout <branch>`
    - Useful for 1) checking out the master or development branch, 2) checking out an upstream branch, and 3) checking out a feature branch
- Create a new branch: `git checkout -b <branch>`
- Delete a branch when you're done with it: `git branch -d <branch>`

## Less common commands

- Removes files to commit: `git rm <files>`
- Delete all local changes in the repository: `git clean -f`
- Show all the diffs and changes from the last N commits: `git log -p -<N>`
- Show the differences between your repository and a remote one: `git log -p master..<REMOTE>/master`
- View all remotes for the current repository: `git remote -v` (e.g. GitHub mirror, friend's fork, upstream, etc.)
- Show the entire contents of a commit, including diffs: `git show <commit>`
- Search for a string in the files of a git repository: `git grep <pattern>` **OR** `gg <pattern>`
    - Search for any tab characters in a repository: `git grep $'\t'` **OR** `ggt`
    - Search for any carriage returns in a repository: `git grep $'\r'` **OR** `ggr`
- Merge all unpushed commits into a single commit: `git rebase -i origin/master`
    - Note that you are not done after this. You must also change `pick` to `squash` (or `s`) for all of the commits you want to merge. This is usually everything except your most recent commit.
    - Another window will open to let you combine all the commit messages into one big commit message

### Working with Tags

- Show all the tags in a repository: `git tag`
- Create a new tag: `git tag -a <tag_name> -m <description>`
    - If `-m` is not given, git will open your editor to allow you to type a more detailed message
    - The tag name is usually a version number such as `v2.4.3`
- View the saved data of a tag: `git show <tag_name>`
- Tag a specific commit instead of the current state in the repository: `git tag -a <tag_name> <commit>`
- Push a tag to the remote repository: `git push origin <tagname>`
    - Note that sharing a tag is the same as sharing remote branches
- Push all tags to upstream: `git push --tags`
- Easily change between versions of a repository (through tags): `git checkout <tag_name>`
- Update a previous version with new changes: `git checkout -b <branch_name> <tag_name>`
    - Note that you should make a new tag for the updated commit since `<tag_name>` already refers to a commit and is not changed
    - For example, if you checkout tag `2.0` then the new tag can be, for example, `2.0.1` or `2.0a`