> For the complete documentation index, see [llms.txt](https://yu-sun.gitbook.io/essential-git-for-scientists/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yu-sun.gitbook.io/essential-git-for-scientists/basic-operations/extend-a-branch.md).

# Extend a Branch

Branches are comprised of commits. Any new commit is made at the tip of a branch, causing the branch to grow.

Now let's make a commit in the `new` branch:

* A new file is created with `import this` as the content.
* The file is staged and commited

```bash
λ echo import this > newfile.py

λ cat newfile.py
import this

λ git commit -am "Added new file"
On branch new
Untracked files:
  (use "git add <file>..." to include in what will be committed)
        newfile.py
nothing added to commit but untracked files present (use "git add" to track)

λ git commit --am "Added new file"
error: pathspec 'Added new file' did not match any file(s) known to git

λ git add newfile.py

λ git commit -m "Added new file"
[new e84601c] Added new file
 1 file changed, 1 insertion(+)
 create mode 100644 newfile.py
```

If we look at the commit history now, you will see HEAD is pointing to `new` and it's one commit ahead of `master`.

```bash
λ git log --oneline
e84601c (HEAD -> new) Added new file
a37231a (master) Revert "Added another file"
35ac407 Added another file
ee7ebbd Print out the std dev
b1e55d3 Print out the mean
c96c526 First commit
```


---

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