# Filesystem and user directory

Your notebook server is a linux "virtual machine" with its own filesystem.
You are not on a shared server; you are on your own private server.

The easiest way to move files in and out of your home directory is via the JupyterLab web interface.
Drag a file into the file browser to upload, and right-click to download back out.
You can also open a terminal via the JupyterLab launcher and use this to ssh / scp / ftp to remote systems.
However, you can’t ssh in!

## Your Home Directory

Your username is ``jovyan``, and your home directory is ``/home/jovyan``.
This is the same for all users, but no one else can see or access the files in *your* home directory.

``/home/jovyan`` is a persistent network-attached drive. Any files you put there will be there when you
log out and log back into the JupyterHub.

The ``/home/jovyan`` space is intended only for notebooks and code. It's **not** an appropriate place to store
datasets, as it can get really expensive (and slow) when used that way.

### Per-User Storage Quotas

All of our hubs have a 10GB storage quota per-user by default, although this may vary depending on the hub.

You can check how much storage you are using by running the `du` command in a terminal:

```bash
$ du -skh ~
196M    /home/jovyan
```

If you go over the quota limit, then you may experience degraded performance on your server. Contact your hub administrator if you run into any problems.

:::{seealso}
**For hub administrators:** You can monitor disk usage across all users on your hub using the [Home Directory Usage Dashboard](#monitoring:disk-usage) in Grafana.
:::

For temporarily storing large datasets, take a look at the {ref}`/tmp directory<filesystem:tmp>` section below.

For storing data in cloud object storage, see the section [Cloud Object Storage](./object-storage/index.md).

### Modify your bash profile

You may edit your bash profile at `~/.bash_profile`.
However, **be careful** because some edits may have unanticipated consequences.
For example, if you change your shell such that it can no longer launch a Jupyter Server, then your session will fail to start.
This may happen if you **change your default shell** to something like [zsh](https://ohmyz.sh/).

If you change your `~/.bash_profile` and something suddenly breaks, try reverting the change to this file.
If your session can no longer start, [email support](support:email) as this file may need to be manually edited or deleted.

## The `shared` Directory

All users have a directory called `shared` in their home directory.
This is a *readonly* directory - anybody on the hub can *access* and *read from* the `shared` directory.
The hub administrator may choose to distribute shared materials via this directory.
The `shared` directory is not intended as a way for hub users to share data with each other.

(filesystem:tmp)=
## The `/tmp` Directory

Any directory outside of ``/home/jovyan`` is ephemeral on cloud-hosted JupyterHubs. This means if you 
add data or scripts under a writeable directory like `/tmp/myfile.txt` *it will not be there when you
log out and log back in*.

Nevertheless, `/tmp` is a convenient location for storing data temporarily 
because it is a fast SSD drive. The space available depends on your server but will generally be much 
larger than ``/home/jovyan`` (50-100s of GB).